UC-NRLF 


B    3    12M    053 


iiOLOGY 
IBRARY 


PRINCIPLES   OF  HUMAN   NUTRITION 


THE  MACMILLAN  COMPANY 

NEW  YORK    •    BOSTON   •    CHICAGO 
DALLAS   •    SAN   FRANCISCO 

MACMILLAN  &  CO.,  LIMITED 

LONDON   •    BOMBAY   •    CALCUTTA 
MELBOURNE 

THE  MACMILLAN  CO.  OF  CANADA,  LTD. 
TORONTO 


PRINCIPLES 


OF 


HUMAN    NUTRITION 


A  STUDY  IN  PRACTICAL  DIETETICS 


BY 


WHITMAN   H.    JORDAN 

'\ 
DIRECTOR    OF    THE    NEW    YORK    AGRICULTURAL    EXPERIMENT 

STATION;   AUTHOR  OF  "THE  FEEDING  OF  ANIMALS" 


gorfe. 
THE   MACMILLAN    COMPANY 

1912 

All  rights  reserved 


OGY 
G 


COPTBIGHT,   1912, 

BY  THE  MACMILLAN  COMPANY. 


Set  up  and  electrotyped.     Published  January,  1912. 


Norfajooft 

J.  S.  Gushing  Co.  —  Berwick  &  Smith  Co. 
Norwood,  Mass.,  U.S.A. 


PREFACE 

AN  examination  of  this  volume  will  at  once  make  it 
evident  that  it  was  not  prepared  for  use  with  students  who 
have  specialized  in  organic  and  biological  chemistry.  The 
object  in  view  was  rather  such  a  presentation  of  the  subject- 
matter  related  to  human  nutrition  as  would  be  more  or  less 
adapted  to  popular  use,  but  particularly  to  instruction  of 
students  with  moderate  scientific  acquirements,  whether  in 
colleges,  secondary  schools,  short  courses,  schools  of  domestic 
science,  or  correspondence  schools.  The  reliable  knowledge 
bearing  on  the  nutrition  of  man  is  mainly  to  be  found  in 
elaborate  works  on  physiology  and  physiological  chemistry, 
the  contents  of  which  are  not  generally  available.  More- 
over, the  highly  technical  facts  are  usually  not  centered 
around  a  philosophy  of  living.  The  aim  here  has  been  to 
show  the  adjustment  of  this  knowledge  to  a  rational  system 
of  nutrition  without  insisting  upon  adherence  to  technical 
details  that  are  not  feasible  in  the  ordinary  administration 
of  the  family  dietary. 

It  is  needless  to  state  that  the  author  makes  no  claim 
to  having  written  on  his  own  authority,  but,  on  the  other 
hand,  he  has  relied  upon  the  conclusions  of  those  authorities 
and  investigators  whose  sound  scholarship  in  this  field 
of  knowledge  is  unquestioned.  The  following  literature 
is  that  which  has  mainly  been  considered: 


253732 


vi  Preface 

Metabolism  and  Practical  Medicine,  Von  Noorden  ;  trans- 
lated by  J.  Walker  Hall. 

Textbook  of  Physiological  Chemistry,  Abderhalden ; 
translated  by  William  T.  Hall. 

The  Science  of  Nutrition,  Lusk. 

A  Textbook  of  Physiological  Chemistry,  Hammersten; 
translated  by  Mendel. 

Der  Kindes  Enahrung,  Czerny  and  Keller. 

Chemistry  of  Food  and  Nutrition,  Sherman. 

Foods  and  their  Adulteration,  Wiley. 

Physiological  Economy  in  Nutrition,  Chittenden. 

Textbook  of  Physiology,  Howell. 

Textbook  of  Physiological  and  Pathological  Chemistry, 
Bunge. 

The  publications  on  human  nutrition  of  the  Office  of 
Experiment  Stations. 

Papers  by  Dr.  L.  B.  Mendel. 

Generous  acknowledgment  should  be  made  to  Lea  & 
Febiger,  Philadelphia,  Pa.,  for  permission  to  use  the  excel- 
lent cuts  from  Anatomy  and  Physiology  for  Nurses  by 
Kimber. 

W.   H.  JORDAN. 

NEW  YORK  AGRICULTURAL  EXPERIMENT  STATION, 
GENEVA,  N.Y.,  October  27,  1911. 


TABLE   OF   CONTENTS 

PART  I 

THE   PRINCIPLES   OF   HUMAN   NUTRITION 
CHAPTER   I 


THE  PLANT  AS  THE  SOURCE  OF  HUMAN  SUSTENANCE 

PAGE 

.     3-5 

1.    The  plant  stores  food  substance 

3 

4 

3.   Relation  of  plant  substance  to  animal  life 

4 

CHAPTER    II 

THE  CHEMICAL  ELEMENTS  INVOLVED  IN  THE  NUTRITION 

OF  THE 

HUMAN  BODY          

.    6-19 

4.    Number  of  elements  involved  .         .         . 

6 

5.    Sources  of  elements          .... 

6 

A.    The  Elements  and  their  Sources 

•  7~li 

6.    Carbon      ....... 

7 

7.    Oxygen     

8 

8.    Hydrogen          

.      10 

9.    Nitrogen  ....... 

.       10 

10.    Sulfur       .         .        .        .        . 

.       12 

11.    Phosphorus       .         .         . 

.       13 

12.    Chlorine    

.       13 

13.    Potassium         

.       13 

14.    Sodium     . 

.       14 

15.    Calcium    ....... 

.  '    14 

16.    Iron  

.       14 

B.    Proportions  of  Elements  in  Plants  and  Animals 

15-19 

17.    In  plants  ....... 

.       15 

18.    In  animals         .         .         . 

.       17 

19.    Ash  elements  in  animal  body   . 

.       18 

vii 

viii  Table  of  Contents 

CHAPTER  III 

PAGE 

THE  COMPOUNDS  OF  HUMAN  NUTRITION      ....          20-62 

A.  Classes  of  Matter         .......         20-23 

20.  Combustible  and  non-combustible    .        .        .        .21 

21.  Organic  and  inorganic 22 

B.  The  Groups  or  Classes  into  which  the  Compounds  in  Plants 

and  Animal  Life  are  Divided       ....         23-62 

22.  Distribution  of  elements  in  the  classes  of  compounds      24 
Water 26-33 

23.  Determination  of  water 26 

24.  Hygroscopic  water  • 27 

25.  Physiological  water  .......      27 

26.  Water  in  living  plants 28 

27.  Proportion  of  water  varies 28 

28.  Much  water  in  immature  plants       .         .        .         .29 

29.  Effect  of  soil  moisture       ......       30 

30.  Water  in  dry  foods 31 

31.  Water  in  the  animal 31 

32.  Effect  of  age  and  condition       .....       32 
Ash 33-40 

33.  Combination  of  ash  elements 34 

34.  Ash  elements  in  plants 35 

35.  Influence  of  manufacturing  processes  and  cooking 

on  the  ash  constituents  of  plant  substance    .         .       37 

36.  The  mineral  compounds  of  the  animal  body     .         .       38 

37.  The  distribution  of  ash  compounds  in  the  animal 

body      . 39 

38.  Forms  in  which  the  ash  elements  exist  in  the  plant 

or  animal 40 

The  Nitrogen  Compounds 40-02 

Protein        . 42-60 

39.  Determination  of  protein 42 

40.  Various  proteins  unlike     .         .   -    .         .        .  -13 

41.  Classification  of  proteins 43 

42.  The  true  proteins 46 


Table  of  Contents  ix 

PAGE 

43.  Ultimate  composition  of  proteins     .         .  46 

44.  Familiar  examples  of  proteins .         .  .         .47 
Simple  Proteins      ........          47-53 

45.  The  albumins    ........       47 

46.  The  globulins 48 

47.  Plant  globulins 49 

48.  Animal  globulins 50 

49.  Glutenins.         .        . 52 

50.  Alcohol  soluble  proteins  ......      52 

51.  Albuminoids 52 

52.  Histones,  protamines .53 

Conjugated  Proteins 54-56 

53.  Nucleoproteins 54 

54.  Glycoproteins 54 

55.  Phosphoproteins       .         .  .  55 

56.  Haemoglobins    ........       55 

57.  Lecithoprotein 66 

Derived  Proteins 56-58 

Primary 

58.  Proteans  and  metaproteins 67 

69.    Coagulated  proteins          ......       57 

Secondary 

60.  Proteoses,  peptones 57 

61.  Important  properties  of  the  proteins         ...       58 

62.  The  unlike  constitution  of  proteins  from  different 

sources  .        .        .        .        .        .        .        .        .59 

Nitrogen  Compounds  that  are  not  Proteins    .         .         .          61-62 
68.    Amides 61 

64.  Extractives 61 

CHAPTER   IV 

THE  COMPOUNDS  OF  HUMAN  NUTRITION  (Concluded)          .          63-83 
Carbohydrates,  Acids,  Fats,  and  Oils        ....          63-83 

65.  Elementary  composition  ......       63 

66.  Classification    .  64 


x  Table  of  Contents 

PAGE 

The  Carbohydrates         .        .        .        .        .        .        .         65-76 

The  Sugars 65-71 

67.  Classification  of  sugars  according  to  structure          .      66 

A.  Mono-saccharides  or  Simple  Sugars     .         .        .          67-68 

68.  Dextrose 67 

69.  Levulose 68 

70.  Galactose 68 

71.  Pentoses 68 

B.  The  Di-saccharides 68-71 

72.  Saccharose 69 

73.  Maltose     .         . 70 

74.  Lactose .        .        .70 

C.  The  Poly-saccharides 71-76 

75.  The  starches 71 

76.  Glycogen 73 

77.  The  pentosans           .......  74 

78.  Galactans,  mannans,  levulans,  dextrans  ...  74 

79.  The  pectin  bodies 74 

80.  Dextrin 75 

81.  Cellulose 75 

The  Acids 77 

Fats  and  Oils 77-83 

82.  Fats  in  grains  and  seeds 78 

83.  Fat  rich  foods 79 

84.  Nature  and  kinds  of  fats 79 

85.  Physical  properties 80 

86.  Milk  fat 81 

87.  Fatty  acids 81 

88.  Ether  extracts . 82 

89.  Lecithins 82 

CHAPTER   V 

THE  DIGESTION  OF  FOOD 84-126 

90.  Digestion  and  assimilation 84 

91.  General  changes  in  food  through  digestion        .        .       85 


Table  of  Contents  xi 

PAGE 

A.  Ferments 86-92 

92.  Organized  ferments 86 

93.  Structure,  distribution    ......  87 

94.  Conditions  of  growth      ......  88 

95.  Results  of  fermentations 88 

96.  Manner  of  action 89 

97.  Unorganized  ferments 91 

B.  The  Mouth 92-95 

98.  Mastication     .         .  .        .         .         .         .92 

99.  The  saliva 93 

100.  The  saliva  and  its  action 94 

C.  The  Stomach        . ' 95-101 

101.  The  gastric  juice 95 

102.  Gastric  enzyms .96 

103.  Gastric  stimuli 99 

D.  Digestion  in  the  Intestines 101-109 

104.  The  bile 102 

105.  Bile  salts 102 

106.  Secretion  of  bile 103 

107.  The  pancreatic  juice 103 

108.  Protein -splitting  enzyms 103 

109.  Steapsin 104 

110.  Amylopsin       ........  104 

111.  Intestinal  juices      .         ......  105 

112.  Intestinal  bacteria  .         .         .         .         .         .         .  105 

113.  Digestion  of  food  as  a  whole 107 

E.  Absorption  of  Food 109-113 

114.  Function  of  lacteals  and  blood  vessels  in  absorp- 

tion       109 

115.  Changes  in  the  walls  of  the  intestinal  tract     .         .111 

116.  Place  of  maximum  absorption         .        .         .         .112 

F.  Feces -.      113-114 

G.  The  Relations  of  the  Different  Food  Compounds  to  the 

Digestive  Processes 114-117 

117.  Digestibility  of  the  proteins 115 


xii  Table  of  Contents 

PAGE 

118.  Digestibility  of  the  carbohydrates  .        .        .         .110 

119.  Digestibility  of  the  fats 117 

H.  Factors  which  may  influence  Digestibility  .        .        .      117-126 

120.  Meaning  of  digestibility 118 

121.  Kind  of  food  ........    'l!8 

122.  Influence  of  food  on  secretion         ....     120 

123.  Mechanical  condition  of  ingested  food    .         .         .     122 

124.  Relish  for  food 123 

125.  The  amount  eaten  .        .        .        .        .        .        .123 

126.  Effect  of  work 123 

127.  Influence  of  accessory  articles  of  food    .        .        .     124 

128.  Influence  of  cooking  food 124 

129.  Influence  of  individual  peculiarities        .         .         .     125 

130.  The  extent  to  which  different  classes  of  food  are 

digested       . 125 

CHAPTER  VI 

THE   DISTRIBUTION  AND   TRANSFORMATIONS    OF    THE  DIGESTED 

FOOD 127-141 

A.  The  Blood 128-130 

131.  Corpuscles 128 

132.  Haemoglobin 128 

133.  Leucocytes 129 

134.  The  plasma 129 

B.  The  Heart    .  130-133 

135.  Circulation 132 

136.  Entrance  of  nutrients 133 

C.  The  Lungs  .         .        .        ...        .        .        .        .      133-135 

137.  Object  of  breathing         . 134 

D.  The  Use  of  Food 135-137 

138.  Builds  tissue 136 

139.  Function  of  oxygen 136 

140.  Protein  not  wholly  oxidized 136 

E.  Elimination  of  Wastes 137-139 

141.  Urea  .        .        .        .137 


Table  of  Contents  xiii 

PAGK 

142.  Mineral  compounds 138 

143.  Carbon  dioxid 138 

144.  Water 138 

F.   The  Liver 139-141 

145.  Function  of  liver .     139 

CHAPTER  VII 

THE  FUNCTIONS  OF  FOOD  COMPOUNDS         ....      142-172 

A.  Scientific  Methods  of  Inquiry 142-147 

146.  A  determination  of  the  elements  essential  to  the 

construction  of  the  human  body  ....     142 

147.  Methods  of  ascertaining  the  functions  of  the  vari- 

ous nutrients  and  the  needs  of  the  human  body 
under  varying  conditions     .         .         .         .         .143 

148.  Necessary  measurements        .....     144 

149.  How  measurements  are  made.     Respiration  calo- 

rimeter       .  145 

150.  Food  balances 146 

151.  Energy  balance  and  use          .        .         .        .        .     147 

B.  The  Functions  of  the  Nutrients 147-157 

152.  Food  used  in  two  general  ways       ....     148 

153.  Forms  of  energy      .......     148 

154.  Functions  of  water 148 

155.  Functions  of  the  mineral  compounds      .        .        .     149 

156.  Phosphorus  and  brain  power  .....     150 

157.  Foods  supplying  mineral  compounds      .         .         .     151 

158.  Functions  of  protein       .         .         .         .         .         .151 

159.  Relative  efficiency  of  the  different  proteins    .        .152 

160.  Protein  used  in  a  variety  of  ways  ....     154 

161.  Functions  of  carbohydrates    .        .         .         .        .156 

162.  Carbohydrates  as  a  source  of  animal  fat         .         .156 

163.  Functions  of  the  fats  and  oils 157 

C.  Food  as  a  Source  of  Energy 157-170 

164.  Manifestations  of  energy        .....     159 

165.  Energy  stored  in  plant  substance    ....     160 


xiv  Table  of  Contents 

PAGE 

166.  Energy  unit 161 

167.  Energy  units  in  food  compounds    .         .        .        .161 

168.  Available  energy 163 

169.  Net  energy 164 

170.  Factors  used  in  computing  food  values  .        .        .  166 

171.  Energy  relations  of  the  several  nutrients        .        .  167 

172.  Heat  relations 167 

173.  The  critical  temperature 169 

D.   The  Nutritive  Interrelation  of  the  Food  Compounds  and 

the  Need  of  Combining  these  in  the  Diet     .        .      170-172 

174.  Carbohydrates  physiologically  economical     .         .     170 

175.  Protein  sparers 172 

CHAPTER   VIII 

LAWS  OF  NUTRITION 173-176 

176.  Foods  source  of  energy  and  building  material         .     173 

177.  Only  digestible  food  available         .        .        .        .173 

178.  Avenues  of  excretion      ......     173 

179.  Uses  of  digested  food 174 

.    180.   Food  balance 175 

181.  Food  requirements  definite 175 

182.  Production 175 

183.  Specific  requirements 176 

184.  Nutrients  interchangeable  in  part  .        .        .        .176 


PART   II 
PRACTICAL  DIETETICS 

CHAPTER   IX 
GENERAL  CONSIDERATIONS    .         .         .        .         .        .         .      179-197 

A.    How  Standard  Dietaries  have  been  Established  .         .      180-186 

185.  Method  of  study 181 

186.  Standard  dietaries 181 

187.  Influence  of  conditions 186 


Table  of  Contents  xv 

PAGE 

B.  Actual    Food    Consumption    as    a    Basis   for    Standard 

Dietaries 186-195 

188.  The  test  of  experience 187 

189.  Variable  individual  demands  .....     188 

190.  Fate  of  excess  food 188 

191.  Experimental  evidence   ......    189 

192.  Possible  errors         .         .        .        .        .         .         .190 

193.  Minimum  nutrition 192 

194.  Energy  requirements  determined  by  energy  output    193 

195.  Reduction  of  energy  requirement  ....     193 

196.  Relation  of  food  and  body  type       .        .        .        .194 

C.  The  Necessary  Protein  Supply 195-199 

197.  Fixed  and  circulatory  protein          .        .         .        .195 

198.  Protein  standards 196 

199.  Demands  on  protein  supply    .....     196 

200.  Protein  and  health 197 

201.  Arguments  against  minimum  protein  supply  .         .     198 

CHAPTER   X 

THE  SELECTION  OF  FOOD  OR  THE  REGULATION  OF  DIET   .      200-213 

202.  Limitations  of  food  standards          ....     200 

203.  Classes  of  foods 201 

204.  Facts  for  guidance 204 

205.  Regulation  of  diet  as  to  quantity  of  dry  matter 

eaten 206 

206.  Regulation  of  diet  with  reference  to  the  combina- 

tions of  nutrients         ......     208 

207.  How  an  ill-considered  diet  may  fail  to  meet  physi- 

ological requirements  ......     209 

208.  Artificial  foods 210 

209.  Two  lunches  for  a  boy  compared    ....     211 

CHAPTER   XI 

THE    RELATION    OF    DIET    TO    THE    VARYING    CONDITIONS    OF 

LIFE 214-225 

210.  Childhood  214 


xvi  Table  of  Contents 

PAGE 

211.  Old  age 215 

212.  Weight 210 

213.  Sex          .    , 217 

214.  Disposition      .         .         .         .        .         .         .         .218 

215.  Work 218 

216.  Increased  use  of  oxygen  from  work        .         .        .  219 

217.  Increased  respiration  and  blood  flow      .        .         .  220 

218.  Fuel  efficiency  with  man 221 

219.  How  fuel  efficiency  is  modified       ....  221 

220.  Obesity 222 

CHAPTER   XII 

FOOD  ECONOMICS 226-245 

A.  Regulation  of  Diet  with  Reference  to  Economy  of  Expen- 

diture            *.  226-237 

221.  The  cost  of  raw  food  materials       .        .        .        .226 

222.  Cheap  and  costly  foods 229 

223.  Cheap  and  costly  meals 231 

224.  Rational  food  selection 236 

B.  Other  Factors  in  the  High  Cost  of  Living   .         .         .      237-241 

225.  Cost  of  distribution  of  foods 238 

226.  Economy  in  buying  foods 240 

227.  Outside  preparation  expensive        ....     240 
(7.    The  Cost  of  Preparing  and  Serving  Food     .         .         .      241-243 

228.  Elaborate  meals  burdensome 241 

229.  A  simple  diet  abundantly  nutritious       .         .         .241 

230.  Examples  of  simple  living       .         .         .         .         .242 
D.    The  Relation  of  Food  Economics  to  Social  Welfare    .      243-245 

231.  Enormous  food  waste 244 

232.  Expense  of  service  and  equipment          .        .        .     244 

CHAPTER   XIII 

SPECIAL  DIETETIC  METHODS 246-259 

A.    Vegetarianism 246-257 

233.  Anatomical  considerations  247 


Table  of  Contents  xvii 

PAGR 

234.  Is  flesh  protein  necessary  ?.....     248 

235.  The  harmfulness  of  a  mixed  flesh  and  vegetable 

diet 249 

236.  Bacteria  in  foods     .         .        ...         .  .  250 

237.  Bacteria  abundant  in  intestines      ....  250 

238.  Relation  of  foods  to  intestinal  bacteria  .        .         .  250 

239.  Flesh  foods  containing  uric  acid  formers        .         .  252 

240.  Purins  in  vegetable  foods 252 

241.  Danger  from  toxins 254 

242.  The  physical  quality  of  flesh  eaters  as  compared 

with  vegetarians 255 

243.  General  considerations  as  to  meat  eating        .        .     256 
B.   Eating  Raw  Foods 257-259 

244.  Mastication 258 

245.  Digestibility 258 

246.  Influence  of  cooking  on  function    ....    258 

CHAPTER   XIV 

THE  NUTRITION  OP  THE  CHILD    ......      260-299 

A.  The  Nourishment  of  the  Foetus 260-266 

247.  Growth  of  foetus 260 

248.  Sources  of  fetal  growth  .         .         .         .  .262 

249.  Food  demands  during  pregnancy    ....     263 

250.  Energy  used 263 

251.  Diet  of  pregnant  woman          .....     265 

B.  Feeding  of  the  Child  after  Birth  with  Mother's  Milk        266-278 

252.  Mother's  milk  best 266 

253.  The  composition  of  human  milk     ....     266 

254.  Conditions  affecting  mother's  milk         .        .         .     269 

255.  Period  of  lactation 269 

256.  Individuality .270 

257.  Demands  on  food  for  milk  secretion       .        .        .     270 

258.  Necessary  dietary   .......     272 

259.  Effect  of  insufficient  diet 272 

260.  Effect  of  foods  on  milk  secretion  272 


xviii  Table  of  Contents 

PAGE 

261.  Procedure  when  milk  is  abnormal  '.                     273 

262.  Effect  of  mother's  food  upon  child          .        .         .     274 

263.  Effect  of  food  upon  cow's  milk       .         .        .         .275 

264.  Effect  of  medicines  taken  by  mother      .        .        .276 

265.  Effect  of  psychic  conditions 277 

266.  Precautions  in  feeding    ......     277 

C.  Artificial  Feeding  of  Infants 278-289 

267.  Unlike  composition  of  human  and  cow's  milk        .     278 

268.  Are  the  compounds  similar  ? 280 

269.  Comparison  of  physical  conditions          .         .         .     282 

270.  The  unlike  curdling  of  the  two  milks     .         .         .282 

271.  The  humanizing  of  cow's  milk        .         .         .        .283 

272.  Illustrative  formulae 284 

273.  Accuracy  desirable 280 

274.  Precautions 287 

275.  Goat's  milk  as  infant  food 287 

D.  Infant  Foods 289-293 

276.  Composition  of  infant  foods 290 

277.  Important  facts  about  infant  foods         .         .         .     292 

278.  Danger  from  unmodified  starch      ....     292 

279.  Standard  for  infant  foods 293 

E.  Feeding    the    Child    after    it    has  passed  the  Period  of 

Infancy 293-299 

280.  Introduction  of  solid  food  into  diet         .         .        .  293 

281.  Simple  diet  best 294 

282.  Mixed  diet  desirable 295 

283.  The  candy  habit 295 

284.  Suggestions  for  children's  dietaries         .         .        .  295 

285.  Illustrative  meals  for  children                                   .  297 


CHAPTER   XV 

THE  CHARACTER  AND  FOOD  VALUE  OF  CERTAIN  COMMERCIAL 

ARTICLES        .........      301-311 

A.    Meat    Preparations,    Extracts,     Fluid     Extracts,     Meat 

Juices  301-304 


Table  of  Contents  xix 

PAGE 

286.  True  meat  extract 301 

287.  Commercial  meat  extracts 302 

B.  Breakfast  Foods 304-309 

288.  Sources  and  kinds 304 

289.  Composition 305 

290.  Changes  in  preparation 305 

291.  Digestibility 305 

292.  Unwarranted  claims 307 

293.  Money  cost 307 

C.  Alcohol  in  Nutrition    . 309-511 

294.  Alcohol  is  oxydized  in  body 309 

295.  Relation  to  muscular  effort     .....     310 

296.  Alcohol  not  a  necessary  food 311 

CHAPTER   XVI 
THE  PREPARATION  OF  FOOD 312-319 

A.  Chemical  Reactions  or  Changes  due  to  Specific  Causes    312-314 

297.  The  evolution  of  carbonic  acid        ....     312 

298.  The  coagulation  of  proteins    .....     313 

B.  The  Effect  of  Cooking  or  the  Action  of  Heat  upon  Foods 

in  Roasting,  Frying,  Baking,  and  Boiling   .         .      314-319 

299.  Effect  of  cooking  on  tissues 314 

300.  Losses  in  cooking  meat  ......     315 

301.  Relative  loss  from  meats  by  different  methods  of 

cooking 316 

302.  Losses  in  cooking  vegetables  .....     318 

303.  Relative  loss  from  vegetables  by  different  methods 

of  cooking 318 

304.  Influence  of  cooking  upon  nutritive  efficiency         .     319 

CHAPTER   XVII 

FOOD  SANITATION 320-342 

A.    Cow's  Milk 321-329 

305.  Ways  in  which  quality  of  milk  is  modified     .  .     322 


xx  Table  of  Contents 


PAGE 

306.  What  is  normal  milk  ?    .         .      ,  .         .        .         .322 

307.  Adulteration  of  milk  with  water     ....    323 

308.  Effect  of  adulteration 324 

309.  Milk  standards 324 

310.  The  removal  of  a  portion  9f  the  milk  solids    .         .     325 

311.  The  introduction  into  cow's  milk  of  non-pathogenic 

germ  life 325 

312.  The  introduction  of  pathogenic  germs  after  the 

milk  is  drawn       .......  326 

313.  Infection  of  milk  from  diseased  cows      .         .         .  327 

314.  The  precautions  necessary  to  procure  pure  milk    .  327 

315.  Pasteurization  of  milk  as  a  safeguard  against  the 

effects  of  pollution 329 

B.  Water  as  a  Source  of  Disease      .        .        .        .        .      329-332 

316.  Pure  water 330 

317.  The  impurities  of  water 330 

318.  Certain  precautions  are  necessary  to  insure  sani- 

tary water  for  domestic  use         .         .        .         .331 

C.  Relation  of  Ice  to  Health 332-334 

319.  Does  ice  ever  carry  disease  germs  ?  333 

D.  Unhealthy  Meats  and  Vegetables        ....      334-338 

320.  Trichinosis .         .335 

321.  Tuberculosis 335 

322.  Raw  oysters  as  a  source  of  disease          .         .         .     336 

323.  Conveyance  of  infectious  diseases  by  fruits  and 

vegetables    .        .        .         .        .        .        .        .    337 

324.  Cooking  as  a  safeguard  against  disease  .        .         .     337 

325.  Toxic  effect  of  fermented  meats  and  milk  products    338 

E.  Effect  of  Food  Preservatives  upon  Health  .         .         .      338-342 

326.  Should  the  use  of  preservatives  in  food  products  be 

permitted? 339 

327.  Use  of  food  preservatives  a  doubtful  policy    .         .341 

328.  Use  of  food  preservatives  promotes  careless  methods    342 


Table  of  Contents  xxi 

CHAPTER  XVIII 

PAGE 

THE  PRESERVATION  OP  FOODS     .        .         .        .         .         .      343-348 

329.  Factors  involved      .        .         .  .         .        .     343 

330.  Moist  foods     . 343 

331.  Dry  foods 344 

332.  The  cellar  as  a  storage  place 345 

333.  Canning  and  preserving 346 

334.  Insects .        .347 

DIAGRAMS  OP  CUTS  OF  MEATS  FROM  VARIOUS  ANIMALS    .      348-350 
CHEMICAL  COMPOSITION  -OF  AMERICAN  FOOD  MATERIALS  .      351-443 


PART   I 

THE  PRINCIPLES  OF  HUMAN  NUTRITION 


PEINCIPLES  OF  HUMAN  NUTEITION 


CHAPTER  I 

THE    PLANT    AS    THE    SOURCE    OF    HUMAN 
SUSTENANCE 

THE  vegetable  world  sustains  a  fundamental  relation  to 
man's  physical  being.  Plant  life  is  the  medium  through 
which  the  inorganic-  substances  of  the  soil  and  air  are 
made  available  to  the  uses  of  the  human  organism;  and 
so  it  is  with  the  materials  and  activities  of  plants  that 
we  must  begin  a  study  of  the  basal  facts  of  human  nutrition. 

1.  The  plant  stores  food  substance.  —  The  first  step 
toward  supplying  man  with  food  is  taken  when  the 
farmer  drops  seed  into  the  warm  earth.  As  soon  as 
the  young  rootlets  from  a  germinating  seed  come  in 
contact  with  the  soil,  and  the  first  leaves  reach  the 
air,  assimilative  growth  begins.  During  the  hours  of 
sunlight,  matter  is  constantly  gathered  in  an  invisible  way, 
which,  after  transformation  into  various  compounds,  is 
added  to  the  enlarging  tissues  of  the  plant.  This  con- 
tinues, perhaps  for  a  season,  until  the  stalk  of  grain  has 
reached  its  full  height  and  has  attained  the  ultimate 
object  of  its  existence  in  the  production  of  seed.  The 
farmer  carries  to  the  field  a  few  pounds  of  seed,  and  he 
returns  to  his  storehouses  laden  with  tons  of  new  material, 
perhaps  hay,  perhaps  grain.  From  somewhere,  in  some 
way,  the  plant  has  gathered  various  substances,  often  no 
less  than  ten  thousand  pound  per  acre  in  a  single  year,  and 

3 


4  '  Principles  of  Human  Nutrition 

has  manufactured  them  into  forms  that  are  nutritively 
useful  to  man. 

2.  The    plant    stores    energy.  —  Plant    life    not    only 
builds  tissue :  it  stores  energy,  as  we  may  easily  discover. 
The  farmer's  boy  learns  this  when  he  feels  the  hot  glow 
of  the  fire  that  is  fed  by  forest  wood.     The  wood  disap- 
pears, but  he  is  warmed  by  the  radiant  heat.     It  has  oc- 
curred that  when  fuel  was  scarce  and  costly  and  grain 
was  abundant  and  cheap,  the  Western  farmer  has  burned 
his  corn.     As  with  the  wood,  the  materials  which  were 
collected  from  the  soil  and  air  were  dispersed  in  invisible 
forms  during  the  combustion  which  liberated  the  heat 
energy,  except  a  small  heap  of  ashes  on  the  hearth. 

3.  Relation  of  plant  substance  to  animal  life.  —  But 
ordinarily,  the  substance  of  farm  crops  is  produced,  not 
for  fuel  but  for  food  purposes,  and  in  this  use  of  vegetable 
matter  we  come  in  contact  with   a  set  of  phenomena 
equally  complex  and  equally  important  and  interesting  to 
those  of  its  growth.     The  child  gradually  attains  a  man's 
stature.    What  is  the  source  of  this  added  tissue?     It  is 
plant  substance  which  in  other  combinations  was  collected 
from  soil  and  air.    The  child  eats  his  daily  food  and  makes 
his  daily  gain  of  tissue.     If  his  food  were  withdrawn,  his 
body  would  waste,  and  in  time  death  would  ensue.     We, 
therefore,  cannot  resist  the  conclusion  that   the  bones, 
blood,  and  flesh  of  the  human  body  are  derived  from  food. 

The  plant  does  more  than  to  supply  building  material 
for  the  animal 1  body,  for  the  living  organism  is  kept  warm. 
No  matter  how  cold  the  surrounding  atmosphere,  we  find 

1  Man  is  an  animal,  and  the  nutritive  processes  of  his  body  are  similar 
to  those  in  all  other  higher  animal  organisms, the  mechanism  being  different. 


The  Plant  as  the  Source  of  Human  Sustenance    5 

\ 

by  the  use  of  a  thermometer  that  in  health  man's  tempera- 
ture remains  at  about  98.4°  F.  with  not  over  one  degree 
normal  variation.  Just  as  the  Western  farmer  obtained 
heat  by  burning  corn  in  the  fireplace,  so  do  human  beings 
maintain  their  body  temperature  at  the  necessary  degree 
by  consuming  food  to.  be  burned.  The  combustion  is  not 
so  rapid  as  occurs  in  the  fireplace,  but  the  chemical  changes 
are  the  same,  only  more  slowly  carried  on. 

Food  not  only  builds  man's  body  and  warms  it,  —  it 
furnishes  it  with  motive  power.  The  energy  which  the 
plant  acquires  during  its  time  of  growth  through  vital 
processes  is  transformed  in  part  into  motion.  Man  is  a 
living  mechanism,  a  combination  of  muscles  and  levers 
which  are  moved,  not  by  means  of  a  spontaneous  internal 
generation  of  energy,  but  through  a  supply  from  without, 
the  energy  stored  in  the  plant. 

If  we  use  the  plant  for  fuel,  we  get  heat  alone;  if  it  is 
consumed  as  food,  we  get  heat,  motion,  and  the  production 
of  body  tissue.  In  the  first  instance,  the  plant  substance, 
except  the  mineral  portion,  is  wholly  broken  up  into 
simpler  compounds  which  escape  in  unseen  gaseous  forms, 
the  liberated  energy  becoming  manifest  as  heat.  If  the 
plant  is  used  by  man  as  food,  a  greatly  varying  proportion 
of  its  dry  matter  is  retained  to  form  his  body  substance, 
and  the  remaining  part  suffers  oxidation,  largely  into  the 
same  compounds  that  are  carried  away  by  the  draft  from 
the  fire  on  the  hearth,  with  an  accompanying  liberation 
of  energy  that  manifests  itself  in  motion  and  heat.  As  a 
result,  there  is  built  a  living  organism  that  is  warmed  to 
a  temperature  generally  much  above  that  of  the  surround- 
ing air,  and  which  is  the  seat  of  complex  internal  activities 
and  is  capable  of  performing  external  work. 


CHAPTER   II 

THE   CHEMICAL   ELEMENTS    INVOLVED   IN 
THE   NUTRITION   OF    THE   HUMAN   BODY 

THE  facts  which  are  fundamentally  necessary  to  a  broad 
understanding  of  human  nutrition  pertain,  first  of  all,  to 
the  materials  out  of  which  vegetable  and  animal  tissues 
are  constructed.  It  is  important  to  know  both  what  these 
are  and  what  are  their  sources. 

4.  Number    of    elements    involved.  —  About    seventy 
substances   are   now  believed  to  be  chemical  elements, 
i.e.,  substances  that  cannot  be  resolved  into  two  or  more 
simpler  ones,  and  of  which,  so  far  as  known,  all  forms  of 
matter  are  composed,  the  variety  of  their  combinations 
being  almost  infinite.     It  is  remarkable  that  comparatively 
few  of  these  fundamental  substances  —  about  one-fifth 
—  are  intimately  related  to  the  growth  of  plants ;    and 
those  that  occupy  a  prominent  place  in  human  nutrition 
are  even  less  in  number.     It  is  necessary  to  mention  only 
fifteen  elements  in  this  connection,  some  of  which  are  of 
minor  importance :    carbon,  oxygen,  hydrogen,  nitrogen, 
sulfur,  phosphorus,  chlorine,  silicon,  fluorine,  potassium, 
sodium,  calcium,  magnesium,  iron,  and  manganese. 

5.  Sources  of  elements.  —  At  ordinary  temperatures, 
four  of  these,  oxygen,  hydrogen,  nitrogen,  and  chlorine, 
are  gases,  and  the  remaining  ones  are  solids.     Four  are 
constant  and  important  ingredients  of  the  atmosphere; 

6 


The  Chemical  Elements;  Carbon  7 

viz.,  carbon,  oxygen,  hydrogen,  and  nitrogen,  and  they 
also  exist  in  the  soil  in  gases,  as  well  as  in  combination  in 
liquids  and  solids;  the  other  eleven,  though  sometimes 
present  in  the  air  in  minute  quantities,  are  found  to  no 
appreciable  extent  except  as  fixed  compounds  in  water  and 
in  the  crust  of  the  earth,  or  in  plants  and  animals.  Nearly 
all  of  these  elementary  substances  are  absolutely  essen- 
tial to  man's  existence.  From  the  standpoint  of  necessity, 
they  are,  therefore,  nearly  all  of  equal  value ;  but  if  we  take 
into  consideration  the  relative  ease  and  abundance  of 
the  supply,  certain  ones  rise  to  a  position  of  supreme 
importance. 


A.   THE  ELEMENTS  AND  THEIR  SOURCES 

6.  Carbon.  —  This  is  a  familiar  substance  in  common 
life.  Anthracite  coal  and  charcoal  are  examples  of  impure 
carbon.  Graphite  in  lead  pencils  is  also  carbon,  and  so 
are  diamonds.  When  wood  chars  or  food  is  burned  in  an 
overheated  oven,  the  partially  decomposed  materials  be- 
come black,  revealing  the  presence  of  carbon,  the  other 
elements  with  which  it  was  associated  being  driven  out. 

An  immense  quantity  of  carbon  exists  in  the  air,  com- 
bined with  oxygen  as  carbon  dioxid  or  carbonic  acid  gas. 
The  average  proportion  by  weight  of  this  compound  in  the 
atmosphere  is  stated  to  be  .06  per  cent,  and  as  the  weight 
of  a  column  of  air  one  inch  square  is  fifteen  pounds,  it 
follows  that  over  every  acre  of  land  there  is  26.2  tons  of 
carbon  dioxid,  or  7.7  tons  of  carbon.  As  we  know  that 
plants  draw  their  supply  of  this  element  from  the  atmos- 
'phere,  and  as  vegetable  tissue  is  its  only  source  to  animal 


8  Principles  of  Human  Nutrition 

life,  we  are  able  to  assert,  with  confidence,  that  the  carbon 
in  the  tissues  of  the  human  body  was  once  floating  in  space. 

A  long  time  ago,  Boussingault  determined  the  average 
yearly  amount  of  carbon  which  was  withdrawn  from  the 
air  by  the  crops  grown  on  a  particular  field  during  a  period 
of  five  years,  and  found  it  to  be  4615  pounds.  This  is  no 
more  than  is  acquired  by  a  large  crop  of  maize.  As  a 
matter  of  fact,  plants,  as  well  as  animals,  contain  a  larger 
proportion  of  this  element  than  of  any  other,  and  the 
amount  of  this  substance  which  enters  into  the  processes 
of  growth  and  decay  in  the  vegetable  and  animal  king- 
doms is  almost  beyond  comprehension.  It  is  natural 
to  wonder  whether  the  atmospheric  supply  is  equal  to  the 
demand.  Any  anxieties  we  may  have  concerning  this 
should  be  removed  by  learning  that  during  many  years 
the  percentage  of  atmospheric  carbon  has  not  changed 
appreciably.  The  processes  of  decay  on  the  earth's  sur- 
face, the  combustion  of  wood  and  coal  as  fuel  and  of  car- 
bon compounds  by  animal  life,  are  returning  carbon  to  the 
air  as  rapidly  as  it  is  being  withdrawn.  This  is  the  round 
traveled,  —  from  the  air  to  the  plant,  from  the  plant  to 
the  animal,  and  from  the  animal  back  to  the  air,  —  a 
cycle  in  which  this  element  has  been  moving  since  life  began, 
and  in  which  it  will  continue  to  move  so  long  as  life  exists. 

7.  Oxygen.  —  This  element  is,  next  to  carbon,  the  most 
abundant  component  of  vegetable  and  animal  tissues,  and 
it  stands  second  to  none  in  its  relation  to  the  vital  processes 
of  nearly  all  forms  of  life.  It  is  not  a  substance  with  which 
we  are  familiar  by  sight,  because  we  ordinarily  come  in 
contact  with  it  as  a  transparent,  colorless  gas.  We  live 
and  move  in  it,  for  it  is  an  important  and  uniformly  abun- 


Oxygen  9 

dant  constituent  of  the  atmosphere.  The  air  is  over 
one-fifth  oxygen  by  volume,  the  proportion  by  weight  being 
slightly  larger.  More  than  twenty-one  million  pounds 
of  this  element  are  contained  in  the  air  above  a  single 
acre  of  land,  a  quantity  which  remains  remarkably  con- 
stant, and  which  is  surprisingly  uniform  over  the  entire 
surface  of  the  globe.  While  it  is  being  continuously  with- 
drawn from  the  air  for  the  uses  of  life  and  to  maintain  fuel 
combustion  and  processes  of  decay,  it  is,  like  carbon,  con- 
tinuously returned. 

Vast  quantities  of  oxygen  are  also  contained  in  water,  as 
this  compound,  which  fills  the  ocean  and  lakes,  and  is 
abundant  in  the  crust  of  the  earth,  is  nearly  89  per  cent 
oxygen.  It  is  estimated  also  that  the  solids  in  the  crust 
of  the  earth  are  one-half  oxygen.  That  which  enters 
directly  into  the  uses  of  animal  life  is,  however,  chiefly 
that  which  is  derived  from  the  atmosphere  and  water. 

Not  a  plant  grows  or  animal  lives  excepting  through  the 
circulation  of  oxygen,  during  which  it  passes  into  fixed 
combinations  and  back  again  to  the  free  form.  Man 
uses  the  free  oxygen  in  breathing  and  returns  it  to  the 
air  in  part  combined  with  carbon  as  carbon  dioxid.  This 
compound  the  plant  appropriates,  retaining  the  carbon 
for  its  tissues  and  giving  back  the  uncombined  oxygen 
to  the  atmosphere  to  be  again  used  by  animal  life.  All 
decay  and  many  other  chemical  changes  require  the  pres- 
ence of  this  element.  What  we  speak  of  as  fire  is  due  to 
its  union  with  the  elements  of  the  fuel. 

Oxygen  bears  an  indispensable  relation  to  the  mechanical 
forces  that  man  now  employs,  for  it  is  the  agent  which 
maintains  combustion  in  the  furnaces  of  our  industries. 


10  Principles  of  Human  Nutrition 

All  the  activities  of  life  are  intimately  related  to  it.  When 
a  plant  grows,  oxygen  is  torn  from  its  union  with  other 
elements  by  the  dominating  power  of  the  sun's  rays,  and 
energy  is  stored  in  vegetable  tissue.  When  this  tissue  is 
used  as  food,  the  oxygen  returns  to  its  former  combinations 
through  the  opportunities  offered  by  the  vital  processes 
of  the  animal,  and  the  hidden  forces  of  the  plant 
compounds  are  thus  manifested  in  a  variety  of  ways. 
Human  toil  is  sustained  by  the  energy  thus  stored  and 
liberated. 

8.  Hydrogen.  —  This  element,  which,  in  a  free  state, 
is  the  lightest  known  gas,  is  found  abundantly  in  nature 
only  in  combination  with  other  elements.     The  minute 
quantities  which  exist  in  the  air  are  due  to  volcanic  action 
and  possibly  to  decay  under  certain  conditions.     As  a 
manufactured  product,  it  has  an  important  use  in  produc- 
ing intense  heat  and  in  filling  balloons.     Hydrogen  con- 
stitutes about  one-ninth  of  water  by  weight,  and  is  found 
in  a  large  number  of  soil  compounds.     It  is  an  essential 
constituent  of  vegetable  and  animal  tissues,  although  it 
exists  in  the  compounds  of  living  organisms  in  a  much 
smaller  proportion  than  carbon  or  oxygen.     Plants  obtain 
it  largely  from  water,  and  it  is  furnished  to  the  animal 
body  in  water  and  in  other  compounds. 

9.  Nitrogen.  —  Probably  no  element  has  been  given 
more  attention  in  its  relations  to  human  nutrition  than 
has  nitrogen  as  such  and  in  its  compounds.     Like  oxygen, 
it  is  an  invisible,  tasteless,  and  odorless  gas  which  forms 
in  the  free  state  a  large  part  of  the  earth's  atmosphere. 
The  air  has  been  considered  to  be  approximately  77  per 
cent  free  nitrogen  by  weight,  but  the  discovery  of  the  new 


Hydrogen ;  Nitrogen  11 

element,  argon,  which  has  heretofore  passed  as  nitrogen, 
will  slightly  modify  previous  determinations. 

Nowhere  outside  of  the  air,  in  the  tissues  of  living 
organisms,  and  in  certain  mineral  deposits,  does  nitrogen 
exist  in  any  form  in  comparatively  large  quantities.  The 
soil  spaces  contain  it,  and  it  is  taken  into  solution  in  small 
proportions  by  all  natural  waters.  It  is  found  in  the  min- 
eral, as  well  as  organic,  compounds  of  the  soil,  but  in  quan- 
tities which  seem  insignificant  as  compared  with  other 
elements,  such  as  oxygen  and  silicon.  Few  agricultural 
soils  contain  over  one,-half  of  one  per  cent  of  combined 
nitrogen.  Minute  quantities  of  its  compounds  exist  in 
the  atmosphere,  which  are  being  constantly  carried  to  the 
soil  in  rain-water  and  as  constantly  replaced  by  the  am- 
monia from  decomposing  animal  and  vegetable  matter 
and  by  the  products  of  the  oxidation  of  nitrogen  through 
electrical  action  and  combustion.  Notwithstanding  this 
comparatively  small  supply  of  nitrogen  compounds,  they 
play  a  prominent  part  in  human  nutrition  both  commer- 
cially and  physiologically. 

Nitrogen  compounds  are  especially  important  because 
the  available  supply  is  often  dangerously  near  the  demand, 
or  even  below  it.  The  nitrogen  found  in  the  air  is  inert  for 
animal  uses,  and  is  ignored  by  a  large  majority  of  plants. 
Much  of  that  in  the  soil  is  also  unavailable.  Moreover, 
its  immediately  useful  compounds  on  the  farm  are  con- 
stantly subject  to  loss,  —  first  by  processes  of  fermenta- 
tion, such  as  those  in  manures,  which  the  farmer  cannot 
wholly  prevent,  and  second  by  soil  losses  which  are  to  some 
extent  beyond  control.  Many  of  the  commercial  products 
of  the  farm  also  carry  away  much  nitrogen.  The  sources 


12  Principles  of  Human  Nutrition 

of  supply  to  balance  this  outgo  are  the  nitric  acid  and 
ammonia  of  the  rainfall,  the  free  nitrogen  captured  by 
legumes,  and  whatever  comes  from  purchased  fertilizers 
and  foods.  These  facts  relate  primarily  to  plant  produc- 
tion, but  they  also  sustain  an  essential  relation  to  the 
maintenance  of  human  life,  and  cannot  be  ignored  in  a 
discussion  of  the  physical  problems  that  relate  to  human 
welfare. 

Physiologically,  the  nitrogen  compounds  stand  in  the 
front  rank.  They  are  necessary  building  material  for  the 
fundamental  tissues  of  the  animal,  and  are  intimately 
related  to  the  prominent  chemical  changes  that  are  in- 
volved in  growth  and  in  the  maintenance  of  life.  It  is  safe 
to  assert,  too,  that  variations  of  these  compounds  in  the 
food  may  have  an  important  influence  on  health  and  the 
character  of  the  body  structure. 

As  a  result  of  these  conditions  which  relate  to  the  supply 
of  useful  nitrogen  and  to  its  important  role,  we  find  that 
it  has  assumed  a  prominent  place  in  commerce.  For  these 
reasons,  the  control,  even  though  only  partial,  which  the 
farmer  may  now  assume  over  the  income  and  outgo  of  the 
nitrogen  compounds  valuable  to  agriculture  is  a  triumph 
of  modern  science  and  an  important  feature  of  national 
economics. 

10.  Sulfur  is  a  common  and  familiar  substance.  As 
an  element  it  is  not  widely  distributed  in  nature,  but  its 
compounds  are  found  in  all  soils  and  natural  waters,  and 
in  all  the  higher  forms  of  animal  and  vegetable  life.  We 
know  it  as  "  brimstone  "  when  fused  in  sticks,  and  as 
"  flowers  of  sulfur "  when  sublimed  in  a  finejy  divided 
form.  Its  most  common  commercial  compounds  are  sul- 


Sulfur;  Phosphorus;  Chlorine;  Potassium     13 

furic  acid  and  the  sulfates  of  potash,  soda,  lime,  and 
magnesia.  This  element  is  an  essential  part  of  some  of 
the  most  important  animal  tissues,  and  is  supplied  in  food 
in'  the  form  of  the  sulfates  and  in  its  protein  combina- 
tions. 

11.  Phosphorus  occupies   an   important  place   among 
the  elements  of  nutrition.     In  the  uncombined  form  it 
does  not  exist  in  nature,  as  that  found  in  laboratories  is 
produced  only  by  chemical  means.     Its  compounds  are 
found  everywhere.     The  phosphates  of  calcium  and  mag- 
nesium are  widely  distributed  in  soils,  and  large  deposits 
of  calcium  phosphate  are  known,  from  which  is  obtained 
the  crude  phosphatic  rock  that  serves  as  a  basis  for  the 
manufacture  of  commercial  fertilizers.     All  foods  in  their 
natural  forms  contain  phosphorus,  combined  in  certain 
fats  and  nitrogen  compounds  which  stand  in  close  relation 
to  the  vital  processes.     It  is  distributed  in  the  flesh  of  man 
and,   combined  with  calcium  and  oxygen,   constitutes  a 
large  part  of  bone. 

12.  Chlorine,  which  is  a  constituent  of  common  salt, 
is  essential  to  human  nutrition.     At  ordinary  temperatures 
it  is,  in  the  free  state,  a  greenish-colored,  disagreeable  gas. 
When  combined  with  hydrogen,  it  forms  hydrochloric  acid, 
a  compound  which  is  necessary  to  the  digestion  of  food. 

13.  Potassium,   combined  with  oxygen  and  hydrogen, 
gives  us  the  caustic  potash  of  the  market.     The  ashes  of 
all  plants  contain  this  element,  a  familiar  illustration  of 
this  fact  being  the  potassium  carbonate  leached  from  wood 
ashes  by  hot  water  in  the  old-fashioned  way  of  making 
soft  soap.     The  saleratus  formerly  used  in  bread-making 
was  a  potassium  compound.     This  element  is  found  in 


14  Principles  of  Human  Nutrition 

the  flesh  of  animals,  mostly  in  the  form  of  the  phosphate, 
and  is  abundantly  supplied  for  the  purposes  of  nutrition 
by  dietaries  that  are  not  too  largely  made  up  of  artificially 
treated  foods. 

14.  Sodium  is  the  basal  element  of  common  salt  (sodium 
chloride) ;  and  this  is  about  the  only  sodium  compound  we 
need  to  mention,  for  this  is  the  one  that  serves  almost 
wholly  as  a  source  of  this  element  to  human  food.  Sodium 
plays  an  important  part  in  the  digestion  of  food,  because 
it  is  the  basis  of  certain  bile  salts  and  is  concerned  in  other 
ways  in  the  digestive  processes. 

16.  Calcium,  when  united  with  oxygen,  forms  lime, 
which  is  one  of  our  commonest  commercial  articles.  Large 
masses  of  lime  rock,  or  calcium  carbonate,  exist  in  many 
parts  of  the  earth's  surface,  and  every  soil  contains  more 
or  less  of  lime  compounds.  As  compounds  of  this  element 
are  always  found  in  plants  and  in  the  milk  of  all  animals, 
a  mixed  diet  of  unmodified  vegetable  and  animal  foods 
nearly  always  furnishes  a  supply  sufficient  to  me'et  the 
demands  of  animal  life.  The  growing  child  makes  a 
generous  use  of  lime,  because  in  union  with  phosphoric 
acid  it  is  the  chief  building  material  of  the  bony  frame- 
work. A  deficiency  of  food  lime  is  sure  to  cause  abnormal 
development  of  the  bony  structures. 

16.  Iron,  one  of  the  elements  of  living  organisms,  needs 
no  description,  because  its  common  properties  are  familiar 
to  every  one.  Iron  rust  and  iron  ore  are  oxides  of  this 
element,  and  when  the  oxygen  is  removed  from  these,  we 
have  the  bright  gray  metal  of  commerce.  Though  taken 
up  by  plants  and  animals  in  small  quantities  only,  iron 
is  absolutely  essential  to  their  growth  and  welfare,  but 


The  Chemical  Elements  in  Plants  15 

because  of  its  abundance  the  imperative  character  of  the 
demand  is  never  realized  in  ordinary  experience.  It  is 
intimately  related  to  the  Me  processes  of  the  human 
organism. 

B.    PROPORTIONS  OF  THE  ELEMENTS  IN  PLANTS  AND 
ANIMALS 

The  facts  which  have  been  reviewed  concerning  the 
elements  out  of  which  the  tissues  of  plants  and  animals 
are  built  are  properly  supplemented  by  a  statement  of  the 
proportions  in  which  these  are  found  in  living  organisms. 
This  information  is  necessary  to  an  understanding  of  the 
relations  of  supply  and  demand  which  exist  between  the 
vegetable  and  animal  kingdoms  and  the  raw  materials 
of  the  inorganic  world. 

17.  In  plants.  —  It  is  estimated  by  a  German  scientist, 
Knop,  that  if  all  the  species  of  the  vegetable  kingdom, 
exclusive  of  the  fungi,  were  fused  into  one  mass,  the  ulti- 
mate composition  of  the  dry  matter  of  this  mixture  would 
be  the  following :  — 

TABLE    I  % 

Carbon 45.0 

Oxygen       .     .    x. 42.0 

Hydrogen 6.5 

Nitrogen 1.5 

Mineral  compounds  (ash) 5.0 

The  composition  of  various  plant  substances  used  as 
human  food  shows  considerable  variations  from  these 
average  figures. 

Carbon  constitutes  a  larger  proportion  of  the  dry  sub- 
stance of  plants  than  any  other  element,  and  there  is  cer- 


16 


Principles  of  Human  Nutrition 


tainly  no  species  that  is  an  exception  to  this  rule.  Oxygen 
stands  next  in  order,  followed  by  hydrogen,  and  then  nitro- 
gen. It  is  an  important  fact  in  the  economy  of  nature  that 
those  elements  which,  on  the  average,  make  up  93.5  per 
cent  of  the  dry  matter  of  plants  have  as  their  main  source 
either  the  atmosphere  or  water.  Only  a  small  percentage 
of  the  dry  matter  of  food  plants  is  drawn  from  the  dry 
matter  of  the  soil,  and  it  is  this  part  of  plant  substance  which 
is  economically  important  to  those  engaged  in  the  produc- 
tion of  human  food. 

The  elements  of  the  ash  vary  somewhat  in  different 
plants  or  parts  of  plants.  For  illustration,  their  propor- 
tions in  the  dry  matter  of  several  kinds  of  plant  substance 
that  enters  into  the  human  diet  are  given  in  this  connec- 
tion :  — 

TABLE   II 

ASH  ELEMENTS  IN  CEREAL  GRAINS  AND  VEGETABLES1 


03 

00 

3 

H 

tO 

a 

o 

H 

0 

K 
I 

e 

E 

H 
H 

9 

P 

K 

* 

« 

§ 

I 

* 

0 

PQ 

O 

O 

« 

£ 

PH 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Potassium    . 

.51 

.36 

.46 

1.25 

1.89 

1.68 

1.93 

2.27 

2.18 

Sodium    .     . 

.029 

.012 

.039 

.029 

.08 

.86 

1.14 

4.32 

.053 

Calcium  .     . 

.043 

.023 

.08 

.129 

.07 

.44 

.77 

1.40 

.39 

Magnesium  . 

.14 

.135 

.134 

.16 

.112 

.14 

.13 

.63 

.163 

Iron    .     .     . 

.017 

.008 

.026 

.012 

.029 

.038 

.144 

.38 

.038 

Phosphorus  . 

.41 

.29 

.35 

.62 

.28 

.31 

.343 

.74 

.412 

Sulfur      .     . 

.0032 

.0044 

.022 

.049 

.099 

.14 

.19 

.45 

.101 

Silicon     .     . 

.018 

.014 

.57 

.011 

.036 

.06 

.031 

.35 

.036 

Chlorine  .     . 

.006 

.013 

.029 

.065 

.131 

.25 

.66 

1.02 

.183 

1  Calculated  from  Wolff's  "  Aschen  Analysen." 


The  Chemical  Elements  in  Animals 


17 


18.  In  animals.  —  We  are  not  ignorant  of  the  propor- 
tions of  the  chemical  elements  in  the  bodies  of  our  larger 
animals,  including  man.  Lawes  and  Gilbert,  of  England, 
and  the  Maine  Experiment  Station,  in  this  country,  have 
made  analyses  of  the  entire  bodies,  or  nearly  so,  of  steers 
and  other  domestic  animals.  These  results,  combined 
with  our  knowledge  of  the  constitution  of  the  compounds* 
of  the  animal  tissues,  enable  us  to  calculate  very  closely 
the  proportions  of  carbon  and  other  elements  in  the  entire 
body  of  man  and  bovines  :  — 


TABLE    III 


MAN 

FAT  Ox. 
LAWES  AND 
GILBERT 

Two  STEERS, 
2-YR.  OLD. 
MAINE  STATION 

Carbon     ...... 

Per  Cent 

63.1 

Per  Cent 
630 

Per  Cent 
600 

Oxygen     . 

20.2 

13  8 

14  1 

Hydrogen                     .     . 

9.9 

94 

90 

Nitrogen  .                     .     . 

25 

50 

58 

Mineral  compounds  (ash) 

4.3 

8.8 

11.1 

As  the  proportion  of  carbon  is  much  larger  in  the  fats 
than  in  the  other  compounds  of  the  animal  body,  it  is  easy 
to  see  that  the  ultimate  composition  of  the  ox  would  vary 
with  his  condition,  whether  lean  or  very  fat.  The  figures 
given  suffice  to  show,  however,  that  animals,  like  plants, 
contain  much  more  of  carbon  than  of  any  other  element, 
and  that  the  quantities  of  the  remaining  elements  stand 
in  the  same  order  in  the  plant  and  in  the  animal,  the  strik- 
ing differences  being  the  greater  proportion  of  oxygen  in 


18 


Principles  of  Human  Nutrition 


the  former  and  of  carbon  and  nitrogen  in  the  latter.  The 
plant  and  animal  are  alike,  therefore,  in  consisting  chiefly 
of  those  elements  which  are  derived  from  air  and  water. 
Carbon,  oxygen,  and  hydrogen  constitute  from  83  to  86 
per  cent  of  the  bodies  of  fat  oxen  and  steers,  raw  materials 
which  nature  supplies  without  cost,  leaving  less  than  one- 
sixth  of  the  animal  body  to  be  built  from  elements  derived 
from  the  soil  that  have,  in  part,  a  commercial  value  for 
crop  production,  which  is  the  fundamental  consideration 
in  the  production  of  human  food. 

19.  Ash  elements  in  animal  body.  —  In  order  to  com- 
pare the  plant  and  animal,  it  is  desirable  to  consider  the 
elements  found  in  the  ash  or  mineral  portion  of  the  animal 
body.  We  will  return  for  this  information  to  the  analysis 
of  a  fat  ox  made  by  Lawes  and  Gilbert.  These  investiga- 
tors found  that  the  ash,  constituting  8.8  per  cent  of  the  dry 
substance  of  the  entire  body,  was  made  up  as  follows,  the 
mineral  or  inorganic  constituents  of  the  human  body  being 
given  for  comparison  :  — 

TABLE    IV 


Ox 

HUMAN 
BODY 

Phosphorus     

Per  Cent 

1.53 

Per  Cent 

1.13 

Calcium      

2.80 

2  50 

Potassium        

0.26 

0  12 

Sodium       -  

0.20 

0  10 

Magnesium     ... 

007 

007 

Oxygen,  combined  with  the  above       .     .     . 
Silicon,  sulfur       

3.29 
0.65 

0  14 

8.80 

The  Chemical  Elements  in  Animals  19 

Of  the  elements  other  than  oxygen  which  appear  in 
the  ash,  phosphorus  and  calcium  take  a  leading  place 
as  to  quantity,  although  sulfur,  potassium,  and  sodium 
are  essential,  even  if  present  in  relatively  small 
amounts. 


CHAPTER   III 

/ 

THE   COMPOUNDS   OF    HUMAN    NUTRI- 
TION 

THE  human  body  consists  primarily  of  elements,  but  we 
ordinarily  regard  it  as  made  up  of  compounds.  These  are 
groups  of  elements  united  in  such  fixed  and  constant  pro- 
portions that  they  have  as  uniform  properties,  under  given 
conditions,  as  the  elements  themselves.  In  discussing  the 
composition  and  uses  of  human  foods  and  their  relation 
to  the  structure,  composition,  and  activities  of  man  as  an 
organism,  we  refer  chiefly  to  the  compounds  of  carbon 
rather  than  to  carbon  itself.  To  be  sure,  the  investigator 
of  the  problems  of  nutrition  often  conducts  his  researches 
and  formulates  his  conclusions  with  reference  to  the  ele- 
ments, but  when  the  information  he  secures  reaches  the 
language  of  practice,  we  speak  of  proteins,  carbohydrates, 
and  fats.  Commerce  recognizes  these  compounds,  also. 
It  is  necessary,  therefore,  for  the  student  of  human  nutri- 
tion, whether  as  a  scientist  or  as  one  who  would  thor- 
oughly understand  dietetics,  to  become  well  informed 
about  those  substances  that  in  various  proportions  form 
the  organized  structure  of  plants,  and  that  furnish  not 
only  the  energies  that  are  manifested  by  animal  life,  but 
all  the  materials  out  of  which  animal  tissues  are  built. 

A.   CLASSES  OF  MATTER 

Before  passing  to  a  consideration  in  detail  of  the  prox- 
imate constitutions  of  plants  and  animals,  it  is  desirable 

20 


Classes  of  Matter  21 

to  reach  a  clear  understanding  of  certain  broad  divisions 
into  which  we  classify  all  matter,  either  living  or  dead, 
which  has  been  organized  by  the  vital  forces  of  the  various 
forms  of  life. 

20.  Combustible  and  non-combustible.  —  One  of  the 
most  common  and  familiar  phenomena  of  the  physical 
world  is  the  destruction  of  vegetable  or  animal  matter  by 
combustion,  with  the  result  that  only  a  small  portion  of 
the  original  material  is  left  behind  in  visible  and  solid 
forms.  Fuel,  such  as  wood  or  coal,  is  largely  consumed 
when  ignited,  and  we  have  as  a  residue  the  ashes.  If  we 
incinerate  hay,  corn,  or  wheat,  we  get  the  same  result. 
The  gradual  decomposition  of  exposed  dead  vegetable 
or  animal  matter  that  occurs  in  warm  weather  is  a  process 
essentially  similar  to  the  combustion  of  fuel,  only  more 
prolonged.  In  view  of  these  facts,  it  is  customary  to  clas- 
sify all  the  tissues  of  plants  and  animals  into  the  com- 
bustible and  incombustible  portions,  the  former  being 
that  part  of  the  ignited  or  decayed  substance  which  dis- 
appears in  the  air  as  gases,  and  the  latter  the  residue  or 
ash.  It  should  be  well  understood  that  combustion  does 
not  involve  a  loss  of  matter;  only  a  change  into  other 
forms.  If  we  were  to  collect  the  gases  which  pass  off  from 
a  stick  of  wood  that  is  burned,  consisting  mostly  of  car- 
bon dioxid,  vapor  of  water,  ammonia,  and,  perhaps,  cer- 
tain other  compounds  of  nitrogen,  we  would  find  that  their 
total  weight,  plus  that  of  the  ash  residue,  is  even  greater 
than  that  of  the  dry  wood,  because  the  carbon  and  the 
hydrogen  of  the  wood  have  taken  to  themselves  from  the 
air,  during  the  combustion,  an  increased  amount  of  oxygen. 
The  carbon,  oxygen,  hydrogen,  and  nitrogen  of  the  plant 


22 


Principles  of  Human  Nutrition 


or  animal  tissue  belong  mainly  to  the  combustible  por- 
tion, although  two  of  these  elements  are  found  in  the  ash 
compounds.  The  remainder  of  the  fifteen  elements  pre- 
viously named  are  supposed  to  appear  wholly  in  the  ash. 
The  relation  in  quantity  of  the  combustible  and  incom- 
bustible parts  of  vegetable  and  animal  dry  matter  and  the 
wide  variations  in  the  proportions  are  illustrated  below  :  — 

TABLE    V 


COMBUSTI- 
BLE 

NON- 
COMBUSTIBLE 

(ASH) 

Potato  tubers 

Per  Cent 

955 

Per  Cent 
4.5 

A  '  ;i  i/.i  '  kernel 

983 

1  7 

V^Tieat  kernel 

980 

20 

Oat  kernel      
Field  bean      

96.9 
96.4 

3.1 
3.6 

Cucumber       ........ 

86.8 

13.2 

Spinach      

83.6 

164 

Rhubarb    

85  6 

144 

Body  of  fat  ox    

91  2 

88 

The  significance  of  these  facts  is,  that  the  chemical 
change  which  we  call  combustion  is  one  of  the  phenomena 
of  human  nutrition.  Substances  which  may  suffer  either 
slow  or  rapid  oxidation  outside  the  human  organism  may 
undergo  complete  or  partial  combustion  within  this  or- 
ganism; or,  stated  in  another  way,  the  part  of  the  plant 
which  "  burns  up  "  in  the  fireplace  or  crucible  is  the  part 
which  in  general  undergoes  the  same  change  within  the 
human  organism  in  so  far  as  the  food  is  digested. 

21.  Organic  and  inorganic.  —  The  terms  combustible 
and  incombustible  are  less  used,  perhaps,  than  two  others, 


Classes  of  Matter  23 

which  represent  practically  the  same  divisions  of  plant  or 
animal  substance ;  viz.,  organic  and  inorganic.  In  chem- 
ical literature,  the  portion  of  a  plant  or  animal  which 
suffers  combustion  is  called  the  organic,  and  the  ash  is 
known  as  the  inorganic  or  mineral  part.  These  terms  are 
evidently  based  upon  the  erroneous  assumption  that  the 
compounds  which  burn  and  break  up  into  simpler  ones 
are  peculiarly  those  which  sustain  necessary  and  vital 
relations  to  life,  and  are  formed  only  through  the  functions 
of  living  organisms.  As  a  matter  of  fact,  many  of  these 
so-called  organic  compounds  have  been  synthesized  (built 
up)  artificially,  and  while  the  dry  substance  of  the  plant 
is  organized  chiefly  by  building  up  compounds  of  carbon, 
oxygen,  hydrogen,  and  nitrogen,  which  suffer  combustion, 
compounds  of  sulfur,  phosphorus,  chlorine,  potassium, 
sodium,  and  calcium  are  also  constant  and  essential  con- 
stituents of  the  juices  and  tissues  of  the  plant  and  animal ; 
and,  although  the  latter  elements  may  finally  wholly 
appear  in  the  incombustible  part  or  ash,  they  have, 
nevertheless,  sustained  in  other  combinations  important 
relations  to  nutrition  and  growth.  It  is  true,  however, 
that  the  portion  of  a  food  material  which  is  commonly 
spoken  of  as  organic  embraces  those  compounds  that  fur- 
nish practically  all  the  energy  which  is  utilized  by  animal 
life  and  much  the  larger  part  of  the  building  material. 

B.    THE  GROUPS  OR   CLASSES   INTO    WHICH    THE  COM- 
POUNDS IN  PLANTS  AND  ANIMAL  LIFE  ARE  DIVIDED 

The  known  compounds  that  belong  to  life  in  all  its 
forms  are  of  great  number  and  variety,  and  doubtless  many 
are  yet  to  be  discovered.  These  sustain  important  rela- 


24  Principles  of  Human  Nutrition 

tions  to  human  needs,  some  serving  as  food,  some  as 
medicine,  and  some  in  the  arts.  It  is  fortunate  that  com- 
paratively few  must  be  considered  in  discussing  the  science 
of  human  nutrition.  Moreover,  it  is  convenient  that  the 
compounds  which  play  a  leading  part  in  human  nutrition 
are  designated,  especially  for  practical  purposes,  in  classes 
rather  than  singly,  even  though  this  custom  tends  to  more 
or  less  looseness  of  expression  and  definition. 

The  same  classification  is  used  for  the  compounds  of 
both  the  vegetable  and  animal  kingdoms,  and  they  are 
now  divided  into  the  following  general  groups :  — 

Water 

Ash  (mineral  compounds) 

Proteins  (nitrogenous  compounds) 

Carbohydrates 

Fats  (or  oils) 

In  this  instance,  accuracy  is  sacrificed  to  convenience. 
The  class  names  have  come  to  be  regarded,  more  or  less,  as 
representing  entities  having  fixed  properties  and  functions, 
whereas  each  class  contains  numerous  compounds  differ- 
ing widely  in  their  characteristics  and  in  their  nutritive 
value  and  office.  Moreover,  these  terms  have  a  variable 
significance  as  used  under  different  conditions.  No  one  of 
them  except  water  uniformly  represents  just  the  same  mix- 
ture of  compounds  when  applied  to  foods  of  unlike  source. 

22.  Distribution  of  elements  in  the  classes  of  com- 
pounds. —  Before  passing  to  a  detailed  description  of 
these  compounds,  singly  or  in  groups,  it  will  be  well  to 
gain  a  clear  understanding  of  the  relation  which  the  fifteen 
elements  previously  mentioned  sustain  to  these  classes  of 


Distribution  of  Elements 


25 


substances.     This  can  be  seen  most  readily  by  a  tabular 
display. 

Water      .    .    .   [  Oxygen 

I  Hydrogen 


All  vegetable 
or  animal 
matter 


Incombustible 
or  inorganic 
matter 


Ash 


Combustible 
or  organic 
matter 


Proteins  and 
non-proteins 


Carbohydrates, 
fats,  acids     . 


Oxygen 
Sulfur 
Chlorine 
Phosphorus 
Silicon,  Flu- 
orine 
Calcium 
Magnesium 
Iron 

Manganese 
Potassium 
Sodium 

Carbon 

Oxygen 

Hydrogen 

Nitrogen 

Sulfur 

(generally) 
Phosphorus 

(sometimes) 
Iron  (in  a  few 


Carbon 
Oxygen 
Hydrogen 


The  ash,  which,  on  the  average,  constitutes  about  one- 
twentieth  of  the  plant,  and  never  more  than  one-tenth 


26  Principles  of  Human  Nutrition 

of  the  animal,  may  contain  thirteen  of  the  fifteen  elements, 
while  the  larger  proportion  of  living  matter  consists  mostly 
of  the  compounds  of  three  or  four  elements,  in  no  case  of 
more  than  six  or  seven.  From  this  point  of  view,  it  be- 
comes strikingly  evident  that  the  dominant  elements  of  life, 
quantity  alone  considered,  are  those  derived  from  the  air 
and  water. 

Water 

Water  fills  a  very  important  place  in  human  nutrition. 
It  is  everywhere  present,  generally  in  some  useful  way. 
All  plant  substance,  all  animal  tissue,  foods,  and  nearly 
all  the  material  things  with  which  man  comes  in  contact 
in  his  daily  life  are  made  up  of  more  or  less  water,  or  are 
associated  with  it.  Sometimes  this  is  very  evident,  as 
with  green  plants  or  juicy  fruits.  It  is  not  so  evident  with 
wheat,  flour,  and  corn  meal.  If,  however,  we  submit 
almost  any  substance,  no  matter  how  dry  it  may  appear, 
except,  perhaps,  glass  and  metals,  to  the  heat  of  an  oven  at 
100°  C.,  we  find  that  a  material  loss  of  weight  occurs;  and 
if  we  so  arrange  that  whatever  is  driven  off  is  first  drawn 
through  some  substance  that  entirely  absorbs  the  water 
which  has  been  vaporized,  we  learn  that  the  decrease  in 
weight  is  nearly  all  accounted  for  by  the  water  thus  col- 
lected. 

23.  Determination  of  water.  —  This  fact  suggests  to 
us  the  chemist's  way  of  determining  the  proportion  of 
water  which  any  particular  material  contains.  He  weighs 
out  a  certain  amount  of  the  substance  and  then  keeps  it 
in  an  oven  at  212°  F.  for  five  hours,  perhaps,  after  which 
it  is  reweighed.  The  difference  in  the  two  weights,  or  the 
loss,  is  assumed  to  be  all  water,  and  the  percentage  in  the 


Water  27 

original  substance  is  easily  calculated.  That  portion  of 
the  material  which  is  left  behind  after  the  water  is  evap- 
orated we  call  the  dry  substance,  or  water-free  substance. 

24.  Hygroscopic    water.  —  Water    is    associated    with 
plant  and  animal  tissues  in  two  ways,  hygroscopically  and 
physiologically.     It  is  easy  to  illustrate  the  former  way  by 
an  object  lesson.     If  an  ounce  of  corn  meal  were  to  be 
dried  in  an  oven  as  described,  it  would,  as  stated,  lose  in 
weight.     If  it  were  subsequently  allowed  to  remain  ex- 
posed in  the  open  air,  it  would  return  quite  or  nearly  to 
its  original  weight.      The  loss  would  be  due  to  water 
driven  out,  and  the  gain  to  water  absorbed  from  the  at- 
mosphere, which  we  call  hygroscopic  moisture. 

All  solids  attract  moisture  up  to  a  certain  proportion, 
which  varies  with  the  substance  and  with  the  atmos- 
pheric conditions  that  prevail.  The  surfaces  of  the  par- 
ticles of  matter  are  ordinarily  covered  with  a  thin  film  of 
water  which  is  thicker  on  a  cold,  wet  day  than  on  a  warm, 
dry  day;  and  so  certain  foods,  when  exposed  to  the  air, 
weigh  less  at  one  time  than  at  another,  because  the  per- 
centage of  hygroscopic  water  varies.  An  equilibrium 
will  always  be  established  between  the  attraction  of  a 
substance  for  moisture  and  the  tension  of  the  vapor  of 
water  in  the  surrounding  air,  which  accounts  for  the  effect 
of  temperature  and  of  the  degree  to  which  the  air  is  sat- 
urated with  water  vapor.  As  all  substances  do  not  have 
the  same  attraction  for  moisture,  therefore,  under  similar 
atmospheric  conditions,  one  food  may  retain  more  water 
than  another. 

25.  Physiological  water.  —  Water  that  is  held  physip- 
logically  is  that  which  is  a  constant  and  essential  part  of 


28  Principles  of  Human  Nutrition 

living  organisms,  in  which  relation  it  is  necessary  to  life 
and  performs  certain  important  functions.  These  func- 
tions are  of  three  kinds :  (1)  The  presence  of  water  in  the 
tissues  of  plants  and  animals  gives  them  more  or  less 
firmness  or  rigidity  combined  with  elasticity;  (2)  water 
acts  as  a  food  solvent;  (3)  water  is  the  great  carrier  of 
food  materials  and  of  waste  products  from  one  part  to 
another  of  the  vegetable  or  animal  organism. 

26.  Water  in  living  plants.  —  Water  constitutes  a  large 
proportion  of  the  weight  of  all  living  plants,  especially 
during  the  period  of  active  growth.     The  cured  hay,  as 
any  farmer's  boy  knows,  weighs  much  less  than  did  the 
green  grass  when  it  was  cut,  and  this  loss  in  weight  is  due 
almost  wholly  to  evaporation  of  water  from  the  tissues  of 
the  plant  under  the  influence  of  the  sun  and  wind.     This 
water,  which  is  contained  in  the  tubes  and  inter-cellular 
spaces  of  the  stalk  or  leaf,  is  exactly  the  same  chemical  com- 
pound as  pure  water  found  anywhere  else,  and  has  no 
more  value  for  food,  excepting  that  it  is  pure  and  is  not 
subject  to  the  contamination  which  sometimes  occurs  in 
streams  and  wells.     There  is  no  such  thing  as  the  so-called 
"  natural  "  water  of  plants  which  has  a  peculiar  nutritive 
value  or  function.     Vegetation  water  should  be  distin- 
guished from  sap  or  plant  juice.     Sap  is  more  than  water  ; 
it  is  water  holding  in  solution  certain  substances  such  as 
sugars  and  mineral  salts.     When  the  plant  is  dried,  these 
soluble  compounds  do  not  pass  off,  but  remain  behind  as 
part  of  the  dry  matter. 

27.  Proportion   of  water  varies.  —  The  proportion  of 
water  in  plants  varies  greatly  in  different  species,  and  in 
some  species  according  to  the  stage  of  growth  or  the  sur- 


Water  in  Plants  29 

rounding  conditions.  These  facts  have  more  importance 
than  is  generally  recognized,  because  the  food  value  of 
vegetable  substances  is  influenced  by  the  proportion  of 
dry  matter.  It  is  always  necessary  to  know  the  percen- 
tage of  water  in  vegetables  and  fruits  before  we  can  esti- 
mate their  worth  as  food. 

The  variations  in  water  content  of  the  living  tissues  of 
different  species  of  plants  or  parts  of  plants,  as  well  as  its 
large  proportion,  is  well  illustrated  by  the  following  aver- 
age figures :  — 

TABLE    VI 

WATER  IN  GREEN  VEGETABLES 

PEB  CENT 

Asparagus 94.0 

Cabbage 90.5 

Green  peas 78.1 

Lima  beans 68.5 

Onions 87.6 

Pumpkin « 93.4 

Potatoes  (tuber) 78.9 

String  beans 87.2 

Sweet-potatoes 71.1 

Tomatoes 96.0 

Turnips 89.4 

28.  Much  water  in  immature  plants.  —  Immature 
plants  contain  more  water  than  older  or  mature  ones. 
Young  pasture  grass  is  more  largely  water  than  the  same 
plants  would  be  after  the  seed  is  formed.  This  fact  is 
consistent  with  the  very  rapid  transference  of  building 
material  during  the  active  stages  of  growth.  Analyses 
of  samples  of  timothy  grass  cut  at  the  Maine  State  College 
in  1879,  and  at  the  Pennsylvania  State  College  in  1881, 


30 


Principles  of  Human  Nutrition 


show  the  marked  influence  of  the  stage  of  growth  upon 
the  water  content  of  the  living  plant :  — 

TABLE    VII 

MAINE  STATE  COLLEGE 
Percentage  of  Water 


Nearly  headed  out 
In  full  blossom    . 
Out  of  blossom    . 
Nearly  ripe     .     . 


78.7 
71.9 
65.2 
63.3 


PENNSYLVANIA  STATE  COLLEGE 
Percentage  of  Water 

Highly  Manured 

No  Manure 

Cut  June  6,  heads  just  appearing  .     . 
Cut  June  23,  just  beginning  to  bloom 
Cut  July  5,  somewhat  past  full  bloom 

79.7 

69.7 
61.4 

76.5 
69.1 
60.0 

What  is  true  of  timothy  is  probably  true  of  all  vege- 
tables in  the  perfectly  fresh  state. 

29.  Effect  of  soil  moisture.  —  The  proportion  of  water 
in  plants  is  influenced  by  the  lack  or  excess  of  soil  moisture. 
The  soil,  and  not  the  atmosphere,  is  the  source  of  supply  of 
vegetation  water,  which,  taken  up  by  the  roots,  traverses 
the  plant  and  passes  into  the  atmosphere  through  the 
leaves.  If  the  supply  is  abundant,  the  tissues  are  con- 
stantly fully  charged,  but  if,  by  reason  of  drought,  the  soil 
becomes  very  dry,  the  outgo  of  water  by  evaporation  may 
exceed  the  income.  What  farmer  has  not  seen  his  corn 
with  rolled  leaves  during  an  August  drought !  The  vege- 
tation water  had  fallen  below  the  normal,  or  below  what 


Water  in  the  Animal  31 

was  necessary  to  maintain  the  tissues  in  their  usual  con- 
dition of  rigidity. 

30.  Water  in  dry  foods.  —  The  proportion  of  moisture 
in  flour,  meal,  and  other  food  materials  has  much  to  do 
with  their  preservation  in  a  sound  condition.     New  grains 
when  packed  in  large  masses  are  subject  to  fermentations, 
which  injure  their  quality  and  diminish  their  food  value. 
This  is  due  bo  the  fact  that  sufficient  moisture  is  present 
to  allow  the  growth  of  low  forms  of  life  with  certain  at- 
tendant chemical  changes.     Food  materials  containing  20 
per  cent  or  more  of  water,  when  stored  in  large  quantities 
or   in    closed  vessels,   are    almost    certain   to    heat   and 
become   musty   or   moldy,    always   involving    a    loss   of 
nutritive   value.      It    is    well    if    the   moisture   in   flour 
and   other   stored   cereal   preparations   does   not   exceed 
10  or  12  per  cent. 

31.  Water  in  the  animal.  —  Water  is  an  important  and 
abundant  constituent  of  animal  organisms,  from  the  lowest 
to  the  highest  forms.     The  blood,  which  is  one-twentieth 
or  more  of  the  weight  of  the  human  body  is  approximately 
four-fifths  water.     The  soft  tissues  of  farm  animals  have 
been  found  to  contain  from  44  per  cent  to  75  per  cent, 
according  to  the  species  and  conditions  of  the  animal. 
The  most  extensive  and  complete  analysis  so  far  made  of 
the  entire  bodies  of  animals  were  performed  by  Lawes  and 
Gilbert  at  Rothamsted,  England.     In  this  country  four 
steers  were  analyzed  at  the  Maine  Experiment  Station, 
and  in  the  study  of  human  nutrition  problems  many  de- 
terminations of  water  have  been  made  of  parts  of  the  car- 
casses of  bovines,  swine,  sheep,  poultry,  and  game.     The 
figures  are  as  follows  :  — 


32  Principles  of  Human  Nutrition 

TABLE    VIII 
WATER  IN  ENTIRE  BODY 

PER  CENT 

Ox,  well-fed,  Lawes  and  Gilbert 66.2 

Ox,  half  fat,  Lawes  and  Gilbert .  59.0 

Ox,  fat,  Lawes  and  Gilbert 49.5 

Steer,  17  months  old,  medium  fat,  M.E.S 59.0 

Steer,  17  months  old,  medium  fat,  M.E.S 56.3 

Steer,  27  months  old,  fat,  M.E.S 51.9 

Steer,  27  months  old,  fat,'  M.E.S 52.2 

Calf,  fat,  Lawes  and  Gilbert 64.6 

Sheep,  lean,  Lawes  and  Gilbert 67.5 

Sheep,  well-fed,  Lawes  and  Gilbert 63.2 

Sheep,  half  fat,  Lawes  and  Gilbert 58.9 

Sheep,  fat,  Lawes  and  Gilbert 50.9 

Sheep,  very  fat,  Lawes  and  Gilbert     ........  43.3 

Swine,  well-fed,  Lawes  and  Gilbert 57.9 

Swine,  fat,  Lawes  and  Gilbert 43.9 

Chicken,  flesh 74.2 

Fowl,  flesh 65.2 

Goose,  flesh 42.3 

Turkey,  flesh 55.5 

It  is  very  evident  that,  in  general,  considerably  more 
than  half  of  the  weight  of  the  bodies  of  our  domestic 
animals  consists  of  water,  the  range  in  all  species  and 
conditions  here  mentioned  being  from  42.3  per  cent  to 
67.5  per  cent. 

32.  Effect  of  age  and  condition.  —  The  percentage  of 
water  varies  with  the  species,  age,  and  condition.  Swine 
carry  a  notably  small  proportion.  The  calf's  body,  even 
though  fat,  is  comparatively  watery.  It  is  very  noticeable 
that  with  oxen,  sheep,  and  swine  the  lean  animals  contain 


The  Ash  33 

a  much  larger  proportion  of  water  than  do  the  fat.  This 
does  not  mean  that  in  the  process  of  fattening  the  fat  is 
substituted  for  water,  and  so  expels  it  from  the  organism, 
but  that  the  increase  in  fattening  has  a  much  smaller 
percentage  of  water  than  the  body  in  its  original  lean 
condition.  This  is  well  illustrated  by  the  data  from  two 
independent  investigations  at  Rothamsted  and  at  the 
Maine  Experiment  Station.  The  former  investigation 
showed  that  wh'en  swine,  sheep,  and  oxen  are  fattened,  the 
increase  contained  from  20  per  cent  to  24  per  cent  of 
water,  this  being  half  the  proportion  found  in  the  entire 
bodies  of  the  lean  animals.  The  Maine  Station  results 
established  the  fact  that  in  the  increase  of  two  steers 
from  the  age  of  17  months  to  27  months,  during  which 
time  a  fattening  ration  was  fed,  there  was  42  per  cent  of 
water,  the  bodies  of'  the  younger  steers  having  58.2  per 
cent.  It  is  well  understood  that  beef  from  mature  animals 
"  spends  "  better  than  that  from  young,  the  same  observa- 
tion being  made  in  comparing  lean  and  fat  beef.  Modern 
investigation  shows  clearly  that  the  reason  for  this  lies 
partly  in  the  difference  in  water  content.  Dry  matter, 
and  not  water,  is  the  measure  of  food  value. 

Ash 

The  ash  or  mineral  part  of  plants  or  animals  has  occu- 
pied a  minor  place  in  the  discussions  pertaining  to  the  prin- 
ciples and  problems  of  animal  nutrition.  Much  is  said 
and  written  about  the  carbon  compounds  of  living  organ- 
isms, but  the  compounds  of  the  mineral  world,  in  their 
relation  to  foods  and  to  the  processes  of  growth,  are  gen- 
erally passed  by  with  brief  comment,  much  less  than  would 


34  Principles  of  Human  Nutrition 

be  profitable.  It  is  certainly  desirable  to  gain  a  clear 
understanding  of  the  combinations,  distribution,  and 
functions  of  these  bodies.  Their  importance  as  necessary 
constituents  of  foods  and  animals  is  no  less  than  pertains 
to  the  carbon  compounds,  although  their  scientific  and 
commercial  prominence  as  related  to  animal  nutrition  is 
much  less. 

As  previously  stated,  the  mineral  portion  of  a  plant  or 
animal  is  measured  by  the  ash  or  residue  after  combustion, 
the  principal  ingredients  of  which  are  the  following :  - 

ACIDS  ACIDS 

Hydrochloric  acid  .     .  HC1  Potash K2O 

Sulfuricacid       .     .     .  H2SO4  Soda Na2O 

Phosphoric  acid      .     .  H6P2O8  Lime CaO 

Silicic  acid     ....  SiO2  Magnesia MgO 

Carbonic  acid    .     .     .  CO2  Iron  oxid Fe2O.3 

Other  mineral  compounds  are  found  in  the  ash  from  various 
forms  of  vegetable  life,  but  those  mentioned  are  all  that  we 
need  to  discuss  at  length. 

33.  Combination  of  ash  elements.  —  The  acids  and 
bases  do  not  exist  in  the  ash  as  shown,  but  they  are  united 
to  form  salts,  and  so  we  have  the  chlorides,  sulfates,  phos- 
phates, and  carbonates  of  potassium,  sodium,  calcium,  and 
magnesium.  These  are  nearly  all  familiar  objects  in 
common  life,  as,  for  instance,  sodium  chloride  (common 
salt),  potassium  chloride  (the  muriate  of  potash  of  the 
market),  potassium  sulfate  (the  sulfate  of  potash  of  the 
market),  calcium  sulfate  (of  which  gypsum  or  land  plaster 
is  composed),  calcium  phosphate  (burned  bone  is  chiefly 
this  compound),  potassium  phosphate  (a  compound  of 
phosphoric  acid  and  potash  found  chiefly  at  the  druggist's), 
and  calcium  carbonate  (limestone). 


Ash  in  Plants  35 

It  should  be  remembered  that  the  compounds  in  the 
ash  are  not  necessarily  those  of  the  plant  or  animal.  Dur- 
ing the  process  of  ignition,  organic  compounds  are  broken 
up,  the  acid  and  basic  elements  of  which  enter  into  other 
combinations  in  the  salts  of  the  ash.  Much  of  the  lime  in 
the  ash  is  in  union  with  carbonic  acid,  which  in  the  plant 
may  have  been  associated  with  vegetable  acids,  such  as 
oxalic  and  tartaric,  and  part  of  the  sulfur  and  phosphorus 
of  the  ash  comes  from  the  nitrogen  (protein)  compounds. 

These  salts  differ  greatly  in  their  properties.  Some  are 
soluble  in  water,  others  are  not.  To  the  former  class  belong 
all  the  chlorides,  and  the  potassium  and  sodium  sulfates 
and  phosphates.  The  normal  phosphates  of  calcium  and 
magnesium  are  insoluble  in  water,  but  soluble  in  various 
acids.  These  facts  are  important  in  showing  what  salts 
may  be  found  in  the  plant  and  animal  juices,  and  what 
effect  leaching  with  water  or  other  solvents  might  have 
upon  the  inorganic  portion  of  human  foods. 

34.  Ash  elements  in  plants.  —  The  ash  elements  of 
plants  are  important  in  this  connection  because  they  are 
the  main  source  of  the  same  elements  of  the  human  body. 
These  may  be  held  in  plant  tissue  in  three  ways :  in  or- 
ganic combinations,  as  the  inorganic  salts  of  the  sap,  and 
in  crystals  and  incrustations.  Outside  of  phosphorus 
and  sulfur,  comparatively  little  is  known  of  the  relations 
of  the  important  ash  elements  to  plant  structure.  The 
ash  from  different  plants  and  parts  of  plants  is  by  no  means 
uniform  in  composition  and  quantity,  even  in  the  same 
species  or  class  of  materials,  although  with  the  grains 
there  is  some  degree  of  uniformity  in  this  respect.  Certain 
factors  cause  variations,  such  as  species,  stage  of  growth, 


36 


Principles  of  Human  Nutrition 


fertility,  the  part  of  the  plant,  and  changes  due  to  manu- 
facturing processes,  and  the  variations  which  occur  pertain 
not  only  to  the  amount  of  ash,  but  also  to  its  composition. 
Different  species  of  plants,  and  consequently  different 
foods,  are  greatly  unlike  in  their  content  of  mineral  mat- 
ter. The  figures  below  illustrate  this  fact,  further  confir- 
mation of  which  may  be  had  by  consulting  more  extended 
tables : — 


TABLE    IX 

THE  MINERAL  COMPOUNDS  IN  CERTAIN  VEGETABLES  AND 
GRAINS  * 

(Per  cent  in  the  dry  matter) 


POTASH 

1 

• 
a 
hi 

MAGNESIA 

a 
1 

1 

PHOSPHORIC 
ACID 

SULFURIC 
ACID 

d 

1 

CHLORINE 

Potatoes     .     .     . 

2.27 

0.11 

0.10 

0.19 

.04 

0.64 

0.25 

0.08 

0.13 

Turnips      .     .     . 

3.64 

0.79 

0.85 

0.30 

.06 

1.02 

0.90 

0.15 

0.41 

Carrots       .     .     . 

2.02 

1.16 

0.62 

0.24 

.05 

0.70 

0.35 

0.13 

0.25 

Radishes     .     .     . 

2.32 

1.53 

1.08 

0.22 

.21 

0.78 

0.47 

0.07 

0.66 

Spinach      .     .     . 

2.73 

5.81 

1.96 

1.05 

.55 

1.69 

1.13 

0.74 

1.02 

Parsnips     .     .     . 

2.63 

0.07 

0.55 

0.27 

.05 

0.94 

0.25 

0.08 

0.18 

Winter  wheat 

0.61 

0.04 

0.06 

0.24 

.03 

0.93 

0.01 

0.04 

? 

Oats  (with  hulls) 

0.56 

0.05 

0.11' 

0.22 

.04 

0.80 

0.06 

1.22 

0.03 

Barley   .... 

0.56 

0.06 

0.07 

0.23 

.03 

0.92 

0.05 

0.68 

0.03 

Maize  kernel  .     . 
Peas 

0.43 
1  is 

0.02 
003 

0.03 
0  13 

0.22 
022 

.01 

0? 

0.66 
098 

0.01 
009 

0.03 
0.02 

0.01 
004 

Field  beans     .     . 

1.51 

0.04 

0.18 

0.26 

.02 

1.41 

0.12 

0.02 

0.06 

Wolff's  "  Aschen  Analysen." 


Ash  in  Plants 


37 


We  observe  as  we  study  the  previous  figures  that  phos- 
phoric acid,  potash,  lime,  and  magnesia  are  the  more  prom- 
inent mineral  compounds  in  plants,  and  it  is  with  these  that 
we  find  the  most  marked  variations.  The  dry  matter  of 
vegetables  and  of  peas  and  beans  is  much  richer  in 
potash  and  lime  than  is  that  of  the  cereal  grains,  and  rad- 
ishes and  spinach  have  a  relatively  large  amount  of  iron. 
Other  differences  occur.  The  amount  and  kind  of  mineral 
matter  ingested  in  the  food  may  be  varied  greatly  by  the 
selection  of  food  materials. 

35.  Influence  of  manufacturing  process  and  cooking 
on  the  ash  constituents  of  plant  substance.  —  Many  sub- 
stances utilized  as  human  food,  especially  grain  products, 
have  an  ash  content  that  is  determined  more  or  less  by 
certain  processes  of  manufacture,  especially  milling.  For 
instance,  wheat  flour  is  only  a  part  of  the  kernel,  the  bran 
being  removed.  This  bran,  which  is  the  outside  of  the 
kernel,  is  especially  rich  in  mineral  ingredients,  much 
richer  than  the  inner  part  of  the  kernel. 

TABLE    X 
ASH  CONTENT  OF  WHEAT  AND  ITS  MILLING  PRODUCTS 


WATER 

ASH 

Wheat  kernel       ...          .... 

Per  Cent 

10.2 

Per  Cent 
1.8 

Wheat  flour 

10.6 

0.4 

Wheat  germ    . 

104 

2.7 

Wheat  shorts       

10.1 

3.1 

Wheat  bran     

10.4 

5.9 

38 


Principles  of  Human  Nutrition 


The  whole  kernel  contains  about  2  per  cent  of  ash,  the  bran 
about  6  per  cent,  and  wheat  flour  less  than  .5  per  cent. 
When  vegetables  and  meats  are  cooked  in  water  or  are 
steamed,  the  soluble  salts  are  leached  out,  in  part  at  least. 
36.  The  mineral  compounds  of  animal  bodies.  —  The 
mineral  compounds  of  animals  are  nearly  similar  in  kind 
to  those  of  plants,  but  are  very  different  in  relative  propor- 
tions. This  is  made  plain  by  a  comparison  of  the  figures 

given  below :  — 

TABLE    XI 

ASH  IN  PLANTS  AND  ANIMALS  (PER  CENT) 


o 

a 

^ 

K 

o 

[3 

• 

0  Q 

2    Q 

•^ 

^ 

•< 

S 

a 

£ 

£3 

| 

• 

1 

1 

Q 

s 

a 

& 

J 

02 

3 

02 

V 

o 

Dry  substance 

Maize  kernel  .     . 

1.4 

.43 

.02 

0.03 

.22 

0.66 

.01 

.03 

.01 

Wheat  kernel  .     . 

2.0 

.61 

.04 

0.06 

.24 

0.93 

.01 

.04 

Fresh  bodies 

Fat  ox    .... 

3.9 

.14 

.12 

1.74 

.05 

1.56 

.01 

Fat  sheep    .     .     . 

2.9 

.14 

.13 

1.19 

.04 

1.13 

.02 

Fat  swine    .     .     . 

1.8 

.10 

.07 

0.77 

.03 

0.73 

Potash  is  much  less  prominent  in  the  composition  of 
the  animal  than  is  the  case  with  plants,  and  phosphoric 
acid  and  lime  are  much  more  so.  In  general,  more  than 
80  per  cent  of  the  ash  of  the  animal  body  consists  of  phos- 
phoric acid  and  lime  in  combination  largely  as  calcium 
phosphate,  whereas  these  two  compounds  constitute  less 
than  one-half  of  the  ash  of  maize  and  wheat  kernels. 


Ash  in  Animal  Body  39 

37.  The  distribution  of  ash  compounds  in  the  animal 
body.  —  The  bones  contain  a  very  large  proportion  of  the 
ash  constituents  found  in  the  animal  body,  the  soft  parts 
being  poor  in  mineral  salts.  Usually  the  ash  makes  up 
between  60  and  70  per  cent  of  bone,  and  the  bony  frame- 
work is  from  6  to  9  per  cent  of  the  entire  bodies  of  domestic 
animals.  More  than  80  per  cent  of  the  ash  of  bone  is 
calcium  phosphate,  which  is  associated  with  calcium  car- 
bonate, calcium  fluoride,  calcium  chloride,  and  magnesium 
phosphate. 

The  bones  of  all  species  of  animals,  including  man,  show 
a  remarkable  similarity  of  composition,  the  average  of 
which  would  not  be  far  from  the  following  :  — 

TABLE    XII 
IN  100  PARTS  OF -THE  ASH  OF  BONE  (AVERAGE) 

Calcium  phosphate 83.9 

Calcium  carbonate      .     .     i     ..    . 13.0 

Calcium  in  other  combinations 0.35 

Fluorine 0.23 

Chlorine 0.18 

97.66 

The  muscular  tissue  and  other  soft  parts  of  the  animal 
body  contain  less  than  1  per  cent  of  incombustible  bodies. 
The  ash  from  flesh  is  mostly  phosphoric  acid  and  potash, 
accompanied  by  comparatively  small  amounts  of  soda, 
lime,  and  magnesia  and  minute  quantities  of  chlorine  and 
iron.  Unquestionably,  potassium  phosphate  is  the  pre- 
dominating salt  in  flesh,  as  calcium  phosphate  is  in 
bone. 

The  blood  contains  a  variety  of  mineral  substances,  the 


40  Principles  of  Human  Nutrition 

chief  of  which  is  sodium  chloride,  or  common  salt,  although 
a  small  amount  of  iron  is  present,  having  a  most  impor- 
tant function.  In  the  bile,  soda  is  abundant,  combined 
mostly  with  the  peculiar  organic  acids  of  this  secretion. 
Chlorine  is  a  constant  constituent  of  the  gastric  juice, 
its  presence  as  chlorhydric  acid  being  essential  to 
digestion. 

38.  Forms  in  which  the  ash  elements  exist  in  the  plant 
or  animal.  —  As  has  already  been  suggested,  the  mineral 
elements  are  combined  differently  in  the  ash  from  what 
they  were  in  the  plant  or  animal  substance  before  ignition. 
Because  calcium  or  potassium  phosphate  is  found  in  plant 
ash  or  the  ash  of  animal  tissue,  it  does  not  follow  that 
such  a  compound  existed  in  the  unburned  substance. 
For  instance,  the  phosphorus  in  a  grain  of  wheat  is  com- 
bined in  certain  organic  compounds  such  as  nucleo-pro- 
teins  and  phytin.  Sulfur  exists  in  certain  proteins.  When 
ignition  occurs,  there  is  a  rearrangement  of  the  elements, 
and  we  find  the  phosphorus  and  sulfur  present  in  the  ash 
of  the  wheat  kernel  in  inorganic  salts.  It  is  a  mistake,  in 
most  cases,  to  speak  of  any  food  material  containing  the 
compounds  that  are  found  in  its  ash.  Recent  investiga- 
tions have  demonstrated  the  absence  of  inorganic  phos- 
phorus in  the  cereal  grains,  unless  these  have  been  subjected 
to  fermentation,  when  inorganic  salts  of  phosphorus  may 
be  present. 

The  Nitrogen  Compounds 

The  nitrogen  compounds  of  the  vegetable  and  animal 
kingdoms  have  received  much  attention  from  scientific 
investigators  and  writers  during  the  past  fifty  years.  It 


The  Nitrogen  Compounds  41 

is  quite  the  custom  to  declare  that  certain  members  of 
this  class  of  substances  are  the  ones  most  important  in 
the  domain  of  animal  nutrition,  and  many  writers  have 
given  to  them  so  prominent  a  place  in  discussing  nutrition 
problems  as  to  almost  ignore  the  other  nutrients.  Cer- 
tain investigators  claim,  on  the  other  hand,  that  from  the 
economic  point  of  view  the  function  and  relative  value  of 
protein  have  been  unduly  magnified.  Whatever  may  be 
the  correct  opinion,  it  is  very  evident  that  the  present 
tendency  is  towards  a  fuller  discussion  of  the  office  and 
value  of  the  other  classes  of  nutrients. 

There  can  scarcely  be  any  disagreement,  however, 
concerning  the  general  proposition  that  the  compounds 
of  nitrogen  play  a  leading  part  in  the  processes  and 
economy  of  human  nutrition.  This  is  true  for  several 
reasons :  — 

(1)  The  nitrogen  compounds  are  those  fundamental  to 
the  energies  of  the  living  cells  which  make  up  the  tissues 
of  plants  and  animals.     The  basic  substance  of  the  active 
cell  is  protoplasm,   a  complex  nitrogenous  body,  which 
Huxley  called  "  the  physical  basis  of  life."     Around  this 
primal  substance  seem  to  center  all  vital  activities,  es- 
pecially the  transformation  of  the  raw  materials  of  the  in- 
organic world  into  the  organized  structures  of  plant  life 
and  the    transformations    of  food  compounds    into  the 
tissue  substance  of  the  human  body. 

(2)  These  compounds  are  structurally  essential  to  the 
growth  of  living  tissues  and  to  the  formation  of  milk. 

(3)  Foods  rich  in  nitrogen  have  reached  a  position  of 
great   commercial   importance,  and  they  bear  relatively 
high  market  prices. 


42  Principles  of  Human  Nutrition 

Protein 

For  the  sake  of  brevity  and  convenience,  certain  nitrogen 
compounds  of  human  foods,  both  vegetable  and  animal, 
are  designated  as  a  class  by  the  single  term  protein.  This 
term  includes  such  compounds  as  albumins,  globulins, 
and  similar  or  related  organic  nitrogen  bodies  found  in 
human  foods.  When,  therefore,  it  is  stated  that  a  food 
stuff  contains  a  certain  percentage  of  protein,  reference 
is  made  to  the  total  mass  of  nitrogen  compounds  present, 
which  may  be  many  in  number  and  of  greatly  differing 
characteristics. 

39.  Determination  of  protein.  —  It  should  be  stated, 
by  way  of  preliminary  explanation,  that,  in  the  past,  the 
proportion  of  protein  (total  nitrogen  compounds)  in  foods 
has  been  ascertained  by  determining  the  total  amount  of 
nitrogen  and  then  multiplying  its  percentage  number  by 
the  factor  6.25.  This  method  is  based  on  the  assump- 
tion that  the  average  percentage  of  nitrogen  in  the  proteins 
is  16,  which  is  not  true  to  so  close  a  degree  of  approxima- 
tion as  was  formerly  believed  to  be  the  case.  It  may 
happen  in  some  instances  that  a  determination  made 
in  this  way  is  sufficiently  accurate,  while  in  other  cases 
the  margin  of  error  is  large.  Recent  investigations  with 
perfected  methods  show  percentages  of  nitrogen  in  the 
numerous  single  proteins  found  in  the  grains  ranging  from 
15.25  to  18.78.  These  are  largest  in  certain  oil  seeds  and 
lupines  and  smallest  in  some  of  the  winter  grains.  Prom- 
inent authorities  concede  that  the  factor  6.25  should  be 
discarded,  and  suggest  the  use  of  5.7  for  the  majority  of 
cereal  grains  and  leguminous  seeds,  5.5  for  the  oil  and 


The  Proteins  43 

lupine  seeds,  and  6  for  barley,  maize,  buckwheat,  soja 
bean,  and  white  bean  (Phaseolus),  rape,  and  other  brassicas. 
Nothing  short  of  inability  to  secure  greater  accuracy  jus- 
tifies the  longer  continuance  of  a  method  of  calculation 
which  is  apparently  so  greatly  erroneous. 

40.  Various  proteins   unlike.  —  As    previously  stated, 
protein  is  the  accepted  name  for  a  class  of  compounds. 
Just  how  there  came  about  such  a  grouping  of  a  large  num- 
ber of  substances  under  a  single  head  it  is  not  necessary 
to  consider  in  this  connection,  but  it  should  be  made  clear 
that  the  individual  compounds  which  are  included  under 
this  term  are  in  part  so  unlike  in  chemical  and  physical 
properties  as  to  warrant  the  assertion  that  they  have  but 
little  in  common  except  that  they  contain  nitrogen;   and 
we  may  believe  that  their  unlikeness  in  composition  is  no 
greater  than  the  differences  in  their  nutritive  functions. 
Moreover,   the  total  protein  of  any  particular  foodstuff 
may  be  a  mixture  of  several  individual  proteins.     These 
mixtures  differ  greatly  in  the  individual  cereal  grains. 

It  is  very  evident  that  it  is  not  only  convenient,  but 
necessary,  to  classify  such  a  heterogeneous  group  of  bodies 
into  subdivisions  more  nearly  alike  in  their  characteristics. 
When  we  come  to  consider  doing  this,  we  find  there  has 
existed  a  most  unfortunate  confusion  of  terms. 

41.  Classification  of  proteins. — Some  years  ago  a  system 
of  classification  was  reported  by  a  committee  on  nomen- 
clature, representing  the  Association  of  Agricultural  Col- 
leges and  Experiment  Stations.1 

The  first  classification  given  is  essentially  this  one,  al- 
though there  are  included  in  it  certain  distinctions  very 

1  Report  1898,  pp.  117-123. 


44 


Principles  of  Human  Nutrition 


clearly  set  forth  by  Professor  Atwater  in  a  paper  associated 
with  the  above-mentioned  report. 

In  the  arrangement  adopted  it  was  recognized  that  cer- 
tain nitrogen  bodies  included  under  protein  are  so  unlike 
the  main  and  important  members  of  this  group  as  to  be 
properly  styled  non-protein.  It  is  also  conceded  that  there 
are  simple  or  native  proteins  which  seem  to  stand  in  the 
relation  of  "  mother  "  substances  to  a  large  number  of 
protein  bodies  that  have  been  modified  either  by  various 
external  agencies,  or  are  the  result  of  a  union  of  proteins 
with  compounds  of  another  class. 


f  Albuminoids  < 

[  Albumins 
1  Simple      •!  Globulins 
1      and  allies 

Protein.     Total 
nitrogen  com-  • 
pounds 

'  Proteids 
1  Collagensor 
[     gelatinoids 

(Extractives 

A/T  j-c  j  I  Derived 
Modifiedj      Compound 

.     l. 

[  Acids,  etc. 

Other  nitrogen  compounds  are  included  with  the  pro- 
tein by  the  present  methods  of  chemical  analysis,  such  as 
alkaloids  and  nitrates,  but  these  are  so  uncommon  in 
foods,  or  are  present  in  such  small  quantities,  that  they 
may  be  safely  ignored. 

Quite  recently  committees  representing  certain  scientific 
bodies  *  have  recommended  quite  a  different  classification 
from  the  foregoing.  The  terms  used  in  this  classification 
are  explained  in  the  text  which  follows :  — 

i  Am.  Jour.  Phys.,  Vol.  XXI. 


Classification  of  Proteins 


45 


Proteins 


Simple 


Conjugated 


Non-proteins 


Derived 


Extractives 
Amides 
Amino  acids 


Albumins 

Globulins 

Glutelins 

Alcohol  solubles 

Albuminoids 

Histones 

Protamines 

Nucleoproteins 

Glycoproteins 

Phosphoproteins 

Haemoglobins 

Lecithoproteins 

Primary 
derivatives 


Secondary 
derivatives 


Proteans 
Metaproteins 
Coagulated 
proteins 

Proteoses 
Peptones 
Peptides 


The  two  classifications  are  given  in  this  connection  be- 
cause much  literature  on  nutrition  recognizes  the  former, 
and  the  latter  is  now  more  or  less  in  use.  Certain  differ- 
ences should  be  noted.  In  the  latter  the  term  proteid  is 
abandoned,  and  the  term  albuminoid  is  made  to  refer  to 
the  bodies  classed  as  collagens^or  gelatinoids  in  the  former 
grouping.  Besides,  the  newer  classification  makes  a 
more  minute  division  of  the  proteins  on  the  basis  of  con- 
stitution and  characteristic  properties. 


46  Principles  of  Human  Nutrition 

42.  The   true  proteins.  —  The  proteins    are  the    main 
and  important  nitrogen  compounds  either  in  the  plant  or 
in  the  animal.     The  nitrogenous  bodies  of  seeds  are  little 
else  than  proteins,  while  young  plants,  and  especially  roots, 
such  as  beets  and  turnips,  contain  more  nitrogen  in  the 
non-protein  form.     Proteins    are  the  chief    constituents 
of  muscular  tissue.     Their  chemical  constitution  is  not 
definitely  known.     No  investigator  has  yet  been  able  to 
search  out  their  manner  of  combination,  but  it  is  generally 
considered  to  be  very  complex,  even  to  the  extent  of  sev- 
eral thousand  atoms.     These  bodies  are  constructed  from 
the  simpler  ones  of  the  inorganic  world  through  the  vital 
energies  of  plants,  and  they  apparently  must  come  to 
the  animal  fully  organized. 

43.  Ultimate  composition  of  proteins.  —  The  ultimate 
composition  of  the  proteins,  that  is,  the  proportions  of 
the   elements   which   they   contain,    has   been   carefully 
studied,  and  while  there  are  material  differences  among 
them  in  this  respect,  the  limits  of  variation  are  not  espe- 
cially wide,  as  can  be  seen  from  the  following  figures  taken 
from  Neumeister :  — 

TABLE    XIII 
ELEMENTARY  COMPOSITION  OF  THE  PROTEINS 

PER  CENT  AVERAGE 

Carbon 50.0  to  55.0  52.0 

Hydrogen 6.5  to    7.3  7.0 

Nitrogen 15.0  to  17.6  16.0 

Oxygen 19.0  to  24.0  23.0 

Sulfur 0.3  to    2.4  2.0 

We  see  that  the  number  of  elements  ordinarily  found  in 
the  proteins  is  five,  nitrogen  and  sulfur  being  those  that 


Simple  Proteins  47 

chiefly  distinguish  these  bodies  from  all  others  which 
make  up  the  mass  of  combustible  matter.  Two  other 
elements  are  found  in  certain  of  these  bodies,  as,  for  in- 
stance, phosphorus  in  casein  and  iron  in  a  constituent  of 
blood. 

44.  Familiar  examples  of  proteins.  —  Proteins  are  famil- 
iar objects  in  the  home,  and  their  properties  are  matters  of 
common  observation.     When  the  farmer's  boy  secures  the 
tenacious  cud  of  gum  from  the  fresh  wheat  gluten,  or  when 
the  housewife  watches  the  strings  of  coagulated  albumin 
separate  from  the  cold  water  extract  of  fresh  lean  beef 
that  is  brought  to  the  boiling  point,  or  observes  the  white 
of  an  egg  harden  into  a  tough,  white  mass  as  it  is  dropped 
into  boiling  water;    when  we  note  the  stiffening  of  the 
muscular  tissue  of  the  slaughtered  animal  or  the  rapid 
formation  of  strings  of  fibrin  in  the  cooling  blood,  —  in 
all  these  instances  there  are  manifested  certain  chemical 
or  physical  properties  which  pertain  to  these  most  impor- 
tant and  useful  compounds. 

Simple  Proteins 

45.  The     albumins.  —  There     are    several    albumins. 
They  are  found  in  the  juice  of  plants,  in  certain  liquids 
of  the  animal  body  such  as  the  serous  fluids,  in  muscle, 
blood,  and  milk,  and  abundantly  in  eggs.     Unlike  other 
proteins,  these  compounds  are  soluble  in  pure  cold  water, 
and  when  such  a  solution  is  heated  to  the  boiling  point, 
they  separate  from  the  liquid  by  coagulation  and  become 
insoluble  unless  acted  upon  by  some  strong  chemical. 

When  macerated  beef  is  treated  with  cold  water  the 
albumin  in  it  goes  into  solution,  and  if  this  extract  is  boiled 


48  Principles  of  Human  Nutrition 

to  make  beef  tea,  it  is  a  matter  of  common  observation 
that  the  albumin  separates  in  clotted  masses.  None  re- 
mains in  the  tea.  It  is  well  for  the  housewife  to  know 
that  all  lean  meat  contains  this  substance,  which  by  pro- 
longed treatment  with  cold  water  may  be  removed  to  the 
detriment  of  the  residue. 

The  clear  serous  fluid  which  is  left  after  removing  the 
clot  from  blood  contains  albumin,  which  may  also  be 
coagulated  by  heat.  After  the  casein  is  removed  from 
milk  by  acid  or  rennet,  the  albumin  of  the  milk  remains 
in  the  whey.  It  is  this  which  in  part  causes  milk  to  clot 
if  brought  to  the  boiling  point.  One  of  the  most  familiar 
examples  of  this  class  of  proteins  is  the  white  of  an  egg, 
which,  when  cooking  in  boiling  water,  becomes  a  hard, 
white,  coagulated  mass.  Albumin  in  the  serous  fluids 
and  in  blood  is  called  serum-albumin ;  in  milk,  laet-albu- 
min ;  and  in  eggs,  ova-albumin. 

A  small  proportion  of  the  proteins  of  plants  is  found  to 
be  albumin ;  for  instance,  Osborne  found  .3  to  .4  per  cent 
in  wheat,  .43  per  cent  in  rye,  .3  per  cent  in  barley,  .5  per 
cent  in  soja  beans,  and  some  in  most  seeds.  This  pos- 
sesses essentially  the  same  characters  as  the  animal  al- 
bumin described  previously.  Whenever  a  vegetable  sub- 
stance is  leached  with  water,  it  is  probably  this  protein 
which  would  be  the  first  to  suffer  removal  or  destructive 
fermentation. 

46.  The  globulins.  —  It  is  fully  recognized  that  when 
plant  and  animal  tissues  are  treated  with  water,  but  a  small 
part  of  the  proteins  dissolve.  If,  however,  we  add  to  the 
water  a  mineral  salt,  especially  common  salt  (sodium 
chloride),  sufficient  to  secure  a  10  per  cent  solution,  an 


Simple  Proteins  49 

additional  and  considerable  amount  of  protein  may  be 
extracted.  These  compounds  are  called  globulins,  and 
differ  from  the  albumins  in  being  insoluble  in  pure  water 
and  in  a  saturated  solution  of  certain  mineral  salts,  such  as 
sodium  chloride.  The  globulins  form  an  important  part  of 
the  protein  content  of  plants  and  of  animal  tissues,  both 
in  quantity  and  in  having  a  maximum  nutritive  usefulness. 
47.  Plant  globulins.  —  In  plants  these  proteins  seem 
to  be  especially  abundant  and  widespread.  Our  most 
recent  and  most  reliable  knowledge  of  plant  proteins 
comes  from  investigations  conducted  in  the  laboratory  of 
the  Connecticut  Agricultural  Experiment  Station,  chiefly 
by  Osborne.  In  these  researches  the  seeds  of  many  species 
of  agricultural  plants  were  studied,  all  of  which  were  found 
to  contain  globulins.  In  some  the  proteins  consisted 
largely  of  these  compounds.  The  percentage  content  in 
certain  seeds  was  determined  approximately :  — 

TABLE    XIV 
GLOBULINS  IN  CERTAIN  SEEDS 

PER  CENT  PER  CENT 

Kidney  bean      ....     20.0     Wheat      .     .    ...  0.6 

Cottonseed  meal     .     .     .     15.8     Lentil       .     ...        13.0 

Peas 10.0     Horse  bean  .     .          17.0 

Lupin  .......     26.2     Maize      ...  0.4 

Soy  bean      .     Chiefly  globulin 

The  seeds  of  the  legumes,  as  a  rule,  contain  the  largest 
proportion  of  these  proteins,  the  cereal  grains  having  only 
a  very  small  part  of  their  protein  in  this  form. 

From  present  knowledge,  many  seeds  appear  to  have 
characteristic   globulins  which   differ   among  themselves 


50  Principles  of  Human  Nutrition 

in  their  chemical  properties.  These  have  been  given 
names  derived  from  the  general  names  of  the  species  in 
which  they  are  found.  Thus  we  have  amandin  in  almonds, 
avenalin  in  oats,  corylin  in  walnuts,  excel  sin  from  the 
Brazil-nut,  phaseolin  in  several  species  of  beans,  glycin  in 
the  soy  bean,  maysin  in  maize,  vicilin  in  horse  beans, 
lentils, "and  peas,  vignin  in  the  cow-pea,  and  tuberin  in 
the  potato.  One  globulin  called  edestin  appears  to  be 
quite  generally  distributed  in  the  seeds  of  agricultural 
plants,  having  been  found  in  a  larger  number  than  any 
other  protein  yet  discovered,  including  all  the  cereals, 
castor  bean,  cottonseed,  flaxseed,  hemp,  squash,  and  sun- 
flower, though  it  is  not  abundant  in  any  of  these. 

48.  Animal  globulins.  —  The  animal  globulins  of  which 
we  have  definite  knowledge  are  those  that  exist  in  the 
muscle  and  in  the  blood.  The  names  which  some  of  them 
bear  are  myosin,  fibrinogen,  and  paraglobulin.  If  finely 
divided,  well-washed  muscle  (lean  meat)  is  treated  with  a 
10  per  cent  salt  solution,  first  by  rubbing  it  in  a  mortar  with 
fine  salt,  and  then  adding  enough  water  to  secure  the  proper 
strength  of  solution,  a  globulin  is  dissolved  to  which  the 
name  myosin  has  been  given.  The  view  has  been  generally 
accepted  that  this  compound  does  not  exist  as  such  in 
living  muscle,  but  forms  there  by  coagulation  upon  the 
death  of  the  animal.  This  change  has  been  looked  upon 
as  similar  to  the  coagulation  of  blood  through  the  forma- 
tion of  fibrin,  and  is  regarded  as  the  explanation  of  the 
stiffening  of  dead  muscles  (rigor  mortis).  The  theory  has 
been  broached  that  a  "  mother  "  substance  exists  in  the 
living  muscle,  from  which  myosin  is  formed  in  much  the 
same  way  as  fibrin  is  developed  in  clotting  blood  from  a 

' 


Simple  Proteins  51 

preexisting  body,  but  no  single  view  as  to  exactly  what 
occurs  is  fully  accepted.  There  is,  nevertheless,  a  general 
agreement  that  rigor  mortis  is  due  to  a  clotting  of  the 
muscle,  accompanied  by  marked  chemical  transformations, 
one  final  product  being  myosin.  The  theory  is  advanced 
that  ferments  are  present  in  the  muscle,  to  the  influence 
of  which  these  changes  are  due,  and  without  which  they 
do  not  occur. 

Another  prominent  and  remarkable  globulin  is  the 
fibrinogen  found  in  the  blood.  It  is  common  knowledge 
that  when  blood  is  drawn  from  the  veins  and  cools,  it  clots, 
—  a  phenomenon  which  is  nothing  more  than  the  formation 
of  strings  of  fibrin.  Fibrin  as  such  is  not  found  in  living 
blood,  but  is  one  of  the  products  into  which  fibrinogen  splits 
when  exposed  blood  cools,  probably  because  of  the  in- 
fluence of  a  ferment. '  Stranger  than  all  is  the  fact  that  so 
long  as  the  blood  is  retained  in  the  arteries  and  veins,  even 
if  the  animal  dies  and  grows  cold,  this  clotting  does  not 
appear. 

Serum-globulin  is  a  collective  name  for  several  globulins, 
which  exist  in  blood  serum  and  in  the  other  fluids  of  the 
animal  body,  such  as  lymph  and  its  allies,  including  those 
exudations  which  pertain  to  diseased  conditions,  especially 
dropsical. 

One  more  protein  has  been  generally  classified  as  a 
globulin,  although  differing  in  some  respects  from  the 
other  members  of  this  class,  and  more  recently  is  classed 
as  a  phosphoprotein.  Reference  is  made  to  vi  tell  in, 
which  is  the  principal  protein  in  the  yolk  of  eggs.  It  is 
there  intimately  mixed  with  certain  peculiar  phosphorized 
bodies,  which  we  shall  notice  later. 


52  Principles  of  Human  Nutrition 

49.  Glutenins.  —  These  form  a  large  part  of  nitrogen 
compounds  of  the  cereal  grains  and  possibly  of  other  seeds. 
They  are  insoluble  in  water,  alcohol,  and  neutral  salt  solu- 
tions, but  readily  dissolve  in  very  dilute  acids  and  alkalies. 
The  glufcenin  of  the  wheat,  found  in  the  tenacious  substance 
that  is  left  after  washing  the  starch  out  of  wheat  flour,  is 
the  Jbest-known  protein  of  this  class  and  is  an  important 
constituent  of  wheat  flour,  existing  there  to  over  40  per 
cent  of  the  total  protein. 

50.  Alcohol-soluble    proteins.1  —  Alcohol-soluble    pro- 
teins have  been  found  in  all  the  cereal  grains  so  far  exam- 
ined.    The  principal  ones  to  be  mentioned  are  gliadin  from 
wheat,  zein  from  corn,  and  hordein  from  barley.     Gliadin 
is  practically  as  abundant  in  the  wheat  kernel  as  is  the 
glutenin  with  which  it  is  associated,  the  two  together 
constituting  over  80  per  cent  of  the  total  proteins  of  that 
cereal.     The  proportion  of  gliadin  in  wheat  flour  has  much 
to  do  with  its  quality   for   bread-making   purposes.     It 
appears  that  the  best  bread  flour  contains  about  twice  as 
much  gliadin  as  glutenin. 

51.  Albuminoids.  —  This  term,  according  to  the  classi- 
fication in  common  use  in  the  United  States,  has  been  under- 
stood as  including  various  proteins  such  as  the  albumins, 
and  globulins.     The  latter  classification  recommended  con- 
fines the  term  to  the  proteins  found  chiefly  in  the  animal 
body  in  such  parts  as  the  cartilages,  bones,  feathers,  hair, 
hoofs,  horns,  and  nails.     These  proteins  are  also  obtained 
from  the  threads  of  silkworms  and  from  sponges.     The 
albuminoids  have  group  names,  such  as  collagen  in  carti- 


proposes  the  name  prolamins.    Science,  Vol.  XXVI,  pp.  417- 
427. 


Simple  Proteins  53 

lage  and  bone,  keratins  in  feathers,  hair,  hoofs,  horns,  nails, 
and  similar  exterior  tissues,  fibroin  in  the  threads  of  silk- 
worm, and  spongin  in  the  framework  of  sponges. 

Gelatin,  so  well  known  to  the  housewife,  is  derived  from 
collagen.  It  is  a  matter  of  common  observation  that  when 
meat  containing  tendons  (cartilage)  is  submitted  to  the 
action  of  boiling  water,  there  is  obtained  in  the  extract  a 
gelatinous  substance  which  becomes  evident  when  the 
extract  is  cooled.  This  gelatin  is  insoluble  in  cold  water, 
but  dissolves  in  hot.  As  a  dry  commercial  article,  it  is  a 
tenacious  substance,  which,  when  prepared  in  thin  layers, 
is  transparent.  When  collagen  and  gelatin  are  acted 
upon  by  tannic  acid,  as,  for  instance,  when  the  skin  of  an 
animal  is  treated  with  an  extract  from  hemlock  or 
oak  bark,  the  result  is  a  substance  which  does  not 
putrefy  and  which  gives  to  the  tanned  hide  the  proper- 
ties of  leather.  Gelatin  is  much  used  in  various  food 
preparations. 

It  is  characteristic  of  the  keratins  such  as  hair  and  horn 
that  they  contain  a  relative^  large  proportion  of  sulfur, 
the  analysis  of  horn  and  hair  showing  as  high  as  5  per  cent, 
the  average  amount  in  horn  being  3.3  per  cent.  The 
keratin  bodies  serve  to  give  rigidity  and  wearing  qualities 
to  certain  exterior  animal  tissues. 

52.  Histones,  protamines.  —  The  proteins  in  these  two 
groups  do  not  occur  as  such  in  nature,  and  are  only  obtained 
by  separating  them  from  some  combination.  The  two 
groups  are  alike  in  being  basic  in  character  and  in  being 
found  in  the  spermatozoa  of  fishes.  Histones  have  also 
been  obtained  from  the  blood  corpuscles  of  a  goose  and 
from  the  white  blood  corpuscles  of  thymus  glands. 


54  Principles  of  Human  Nutrition 

Conjugated  Proteins 

53.  Nucleoproteins.  —  These  are  complex,  phosphorus- 
bearing  proteins  that  sustain  an  important  nutritive  func- 
tion. They  are  regarded  as  a  combination  of  nuclein  with 
an  albumin,  the  nucleins  being  compounds  of  nucleic  add 
and  albumin,  and  nucleic  acid  yielding  on  cleavage  phos- 
phoric acid,  certain  nitrogenous  bases  known  as  purins, 
and  in  all  cases  a  carbohydrate. 

The  nucleoproteins  are  associated  with  the  nuclei  of 
the  cells  that  make  up  both  plant  and  animal  tissues,  and 
consequently  are  found  in  the  flesh  of  animals  that  is  used 
for  food.  They  are  relatively  abundant  in  glandular 
tissues  such  as  the  spleen,  pancreas,  thymus  gland,  and 
liver.  The  spermatozoa  masses  of  fishes  are  especially 
rich '  in  these  bodies.  Because  certain  bases  known  as 
purins  which  arise  from  the  cleavage  of  nucleoproteins 
are  regarded  as  the  progenitors  of  uric  acid,  persons  with 
uric  acid  tendency  are  advised  to  avoid  eating  certain 
animal  foods  such  as  beef  and  liver,  or  any  others  known 
to  contain  these  compounds.  Experiments  show  that  the 
feeding  of  certain  tissues  rich  in  nucleoproteins  increases 
the  output  of  uric  acid,  while  adding  to  the  diet  a  large 
amount  of  purin-free  proteins  such  as  albumin  does  not 
have  this  effect. 

54.  Glycoproteins  (Glucoalbumins).  —  These  are  bodies 
that  upon  cleavage  are  decomposed  into  a  protein 
and  a  carbohydrate.  The  best-known  glycoproteins  are 
the  mucins  that  are  secreted,  for  instance,  by  the  mucous 
membranes  of  the  air  passages  and  of  the  alimentary  canal 
and  by  certain  glands  such  as  the  salivary.  Certain 


Conjugated  Proteins  55 

of    these    compounds    contain    phosphorus,    and   others 
do  not. 

55.  Phosphoproteins    (  Nucleoalbumins).  —  Like     the 
nucleoproteins,    these    compounds    contain    phosphorus, 
but  on  cleavage  do  not  yield  the  purin  bases  that  under 
certain  conditions  are  to  be  avoided.     The  best-known 
phosphoprotein   is   the  casein  of  milk,  a  compound  ex- 
ceedingly important  in  human  nutrition,  especially  with 
the  young. 

This  compound  is  a  secretion  of  the  mammary  gland  of 
many  species  of  animals,  and  doubtless  originates  in  the 
contents  of  the  gland  cells.  As  will  be  seen  Jater,  the  casein 
from  different  species  of  mammals  differs  somewhat  in 
chemical  and  physical  properties.  Casein  is  insoluble  in 
water,  but  exists  in  milk  in  suspension.  It  is  not  coagu- 
lated by  heat,  but  curdles  when  a  weak  acid  is  added  to 
milk,  as,  for  instance,  vinegar.  The  same  result  is  pro- 
duced by  a  generous  quantity  of  common  salt.  When 
milk  is  ingested  into  the  human  stomach,  the  casein  coagu- 
lates (the  milk  curdles)  through  the  action  of  a  ferment  in 
the  gastric  juice  (see  p.  90),  and  this  coagulation  is  unlike 
with  milk  from  different  species.  The  action  of  this  fer- 
ment on  casein  is  utilized  in  cheese  making  in  the  develop- 
ment of  a  curd  which,  with  its  inclosed  fat,  is  separated 
from  the  whey  and  pressed  into  compact  masses  and  later 
allowed  to  undergo  certain  changes  due  to  other  ferments. 

Other  phosphoproteins  exist,  one  being  the  vitellin  in 
the  yolk  of  eggs,  which,  as  prepared,  contains  lecithin.  (See 
p.  82.) 

56.  Haemoglobins.  —  Blood   contains  a   peculiar   com- 
pound   known    as    haemoglobin.     When    decomposed,    it 


56  Principles  of  Human  Nutrition 

separates  into  a  protein,  globin,  and  a  coloring  matter 
(pigment),  which,  when  charged  with  oxygen,  is  called 
hcematin.  This  haemoglobin  in  the  blood  of  mammals 
contains,  besides  carbon,  nitrogen,  oxygen,  and  hydrogen, 
sulfur  and  iron.  The  latter  varies  in  per  cent  from  .34 
to  .48,  and  sustains  an  essential  relation  to  the  functions 
of  the  blood.  The  blood  pigment  has  the  property  of 
taking  up  and  releasing  oxygen  with  great  readiness,  carry- 
ing its  load  of  oxygen  out  of  the  lungs,  giving  it  up  to  oxida- 
tion processes  in  various  parts  of  the  body,  and  bringing 
to  the  lungs  in  its  place  the  resulting  carbon  dioxid  to  be 
discharged  into  the  air.  The  blood  changes  color  with  the 
acquisition  and  loss  of  the  oxygen. 

57.  Lecithoproteins.  —  From  the  yolk  of  eggs,  the 
mucous  membranes,  and  the  kidneys,  and  doubtless  from 
other  sources,  are  obtained  a  conjugated  protein  contain- 
ing lecithin.  The  constitution  and  special  function  of  this 
body  are  not  well  understood. 

Derived  Proteins 

These  are  divided  into  primary  and  secondary  protein 
derivatives.  Primary  protein  derivatives  are  those  that 
have  been  slightly  modified  by  the  incipient  action  of  water, 
very  dilute  acids,  or  enzyms,  or  are  the  result  of  the  action 
of  acids  and  alkalies  whereby  products  soluble  in  weak 
acids  and  alkalies  are  formed.  Coagulated  proteins  re- 
sulting from  the  action  of  heat  and  alcohol  are  classed  in 
this  division. 

Secondary  protein  derivatives  are  those  in  which  the 
modifying  changes  (hydrolytic  or  the  taking  up  of  water), 
through  the  action  of  acids  or  enzyms,  have  proceeded 


Derived  Proteins  57 

beyond  the  incipient  stage  with  the  formation  of  bodies 
that  are  soluble  in  water.  In  this  division,  the  most  im- 
portant compounds  are  the  proteoses.  and  the  peptones, 
the  latter  having  suffered  a  greater  change  by  hydrolysis 
than  the  former. 

Primary  Protein  Derivatives 

58.  Proteans  and  metaproteins.  —  When  proteins  are 
acted  upon  by  acids  or  alkalies,  they  are  modified  in  pro- 
portion to  the  strength  of  the  reacting  acid  or  alkali  and 
the  length  of  time  that  the  action  continues.     With  acid 
or  alkalies  of  sufficient  strength,  there,  are  formed  products 
soluble  in  weak  acids  and  alkalies. 

59.  Coagulated   proteins.  —  There   are   several   agents 
which  convert  albumins  and  other  proteins  into  a  coagu- 
lated mass,  such  as  a,  boiling  heat,  alcohol,  and  certain 
neutral  salts  and  the  action  of  an  enzym.     For  instance, 
with  albumin  from  flesh  or  the  white  of  an  egg,  boiling 
water  converts  it  into  a  coagulum  that  .is  insoluble  in  water 
and  is  only  rendered  soluble  by  such  agents  as  acids  and 
alkalies  upon  heating. 

Dropping  a  soluble  protein  into  alcohol  has  the  same 
effect.  Globulins  are,  as  a  rule,  affected  in  the  same  way. 
The  nature  of  this  modification  is  not  known. 

4 

Secondary  Protein  Derivatives 

60.  Proteoses,     peptones.  —  When    various    proteins, 
such  as  an  albumin  or  globulin,  are  subjected  to  the  action 
of  a  weak  acid  or  of  certain  enzyms,  they  undergo  what  is 
known  as  hydrolysis.      This  change  involves  a  cleavage 
(splitting)  of  the  protein  body,  accompanied  by  the  taking 


58  Principles  of  Human  Nutrition 

up  of  the  elements  of  water.  In  this  way  are  formed 
proteoses  and  peptones,  the  latter  being  proteins  that  are 
soluble  in  water.  A  proteose  is  an  intermediate  stage 
between  the  original  protein  and  a  peptone,  and  it  receives 
a  name  according  to  its  source,  as  albumose,  globulose, 
and  caseose,  according  as  an  albumin,  a  globulin,  or  casein 
is  its  source. 

Peptone  was  formerly  regarded  as  the  final  product  of 
enzym  action  in  digestion,  but  we  now  know  that  the 
digestion  of  the  proteins  proceeds  much  farther.  These 
hydrolyzed  bodies  are  found  abundantly  in  the  digestive 
tract  during  digestion,  the  proteoses  as  stated  being  an 
intermediate  stage  of  digestion  between  the  original  pro- 
teins and  the  peptones.  This  means  that  the  formation 
of  the  final  products  of  protein  digestion  is  a  progressive 
step.  Proteoses  and  peptones  may  also  be  obtained  by 
laboratory  methods.  It  should  be  noted  that  commercial 
peptones  are  largely  proteoses. 

61.  Important  properties  of  the  proteins.  —  The  pre- 
vious description  of  the  various  groups  of  proteins  cannot 
be  understood  to  its  fullest  extent  excepting  by  those  who 
have  a  good  knowledge  of  the  fundamentals  of  organic 
chemistry.  Nevertheless,  the  facts  given  serve  to  impress 
the  important  chemical  and  physical  properties  which 
these  bodies  possess,  and  point  to  the  necessity  of  studying 
them  individually  in  their  relation  to  foods  and  nutrition. 
It  is  not  rational  to  speak  of  protein  as  if  the  term  represents 
an  individual  entity;  but  the  members  of  this  general  class 
of  compounds  must  be  considered  by  sub-classes  at  least, 
in  discussing  the  use  of  raw  material  in  cookery  and  in 
meeting  dietary  conditions. 


Constitution  of  Proteins  59 

There  are  several  points  that  the  dietician  should  keep 
in  mind.  One  is  the  solubilities  of  the  different  proteins, 
another  the  effect  produced  upon  them  by  heat,  and  an- 
other their  relations  to  acids  .and  ferments,  — facts  that  will 
develop  more  fully  as  we  proceed.  A  fact  still  more  im- 
portant is  the  varying  constitution  of  the  protein  mole- 
cule, and  consequently  the  possible  variation  in  the  nutri- 
tive function  of  the  individual  proteins. 

62.  The  unlike  constitution  of  proteins  from  different 
sources.  —  We  have  already  seen  that  certain  proteins 
are  particularized  in  part  by  containing  phosphorus, 
others  sulfur,  and  others  iron.  The  significance  of  these 
differences  will  become  evident  as  we  discuss  nutritive 
processes.  A  phosphorus-bearing  protein  may  have,  and 
undoubtedly  does  have,  a  nutritive  function  that  can- 
not be  exercised  by  an  albumin  not  carrying  phosphorus. 

It  is  well  known  that  when  proteins  are  submitted  to 
the  action  of  acids,  alkalies,  and  certain  ferments  (enzyms), 
they  break  up  into  simpler  compounds,  which  we  speak 
of  as  cleavage  products.  It  is  very  significant  that  the 
kind,  and  especially  the  proportions,  of  these  products 
differ  greatly  with  different  proteins.  For  instance,  the 
purin  bases,  which  certainly  sustain  important  physio- 
logical relations,  are  present  in  beef  and  certain  glands  used 
as  food,  but  absent  in  milk  and  eggs.  The  variations  in 
the  decomposition  products  of  certain  vegetable  proteins 
are  striking,  as  also  are  the  differences  in  this  respect 
between  vegetable  and  animal  proteins.  These  cleavage 
products  are  sometimes  spoken  of  as  the  "  building 
stones"  of  the  proteins.  The  following  table  is  worthy 
of  attention :  — 


60 


Principles  of  Human  Nutrition 


TABLE  XV 

COMPOUNDS1  INTO  WHICH  VARIOUS  PROTEINS  ARE  BROKEN  BY 
CLEAVAGE 


*•    H 

GLIADIN 
RYE 

HORDEIN 
BARLEY 

I 

S  « 

EGO 
ALBUMININ 

si 

CHICKEN 
MUSCLE 

• 
a 

00    t> 

3 

£ 

Glycocoll  .     .     . 

0.02 

0.13 

0.00 

0.00 

0.89 

0.00 

2.06 

0.68 

0.00 

Alanine     .     .     . 

2.0 

1.33 

0.43 

2.23 

4.65 

2.22 

3.72 

2.28 



3.00 

Leucine     .     .     . 

5.61 

6.30 

5.67 

18.60 

5.95 

10.70 

11.65 

11.19 

10.33 



Proline       .     .     . 

7.06 

9.82 

13.73 

6.53 

4.23 

3.56 

5.82 

4.74 

3.17 

2.40 

Phenylalanine     . 

2.35 

2.70 

5.03 

4.87 

1.97 

5.07 

3.15 

3.53 

3.04 

1.20 

Glutaminic  acid 

37.33 

33.81 

36.35 

18.28 

23.42 

9.10 

15.49 

16.48 

10.13 

3.50 

Tyrosine    .     .     . 

1.20 

1.19 

1.67 

3.55 

4.25 

1.77 

2.20 

2.16 

2.39 

1.00 

Arginine    .     .     . 

3.16 

2.22 

2.16 

1.16 

4.72 

4.91 

7.47 

6.50 

6.34 



Lysine  .... 

0.00 

0.00 

0.00 

0.00 

1.92 

3.76 

7.59 

7.24 

7.45 

0.30 

Histidine   .     .     . 

0.61 

0.39 

1.28 

0.43 

1.76 

1.71 

1.76 

2.47 

2.55 



Ammonia       .     . 

5.11 

5.11 

4.87 

3.61 

4.01 

1.34 

1.07 

1.67 

1.33 



As  these  compounds  into  which  the  several  proteins  are 
split  may  be  regarded  as  the  building  stones  out  of  which 
the  animal  proteins  are  constructed,  the  foregoing  figures 
are  significant. 

In  this  connection  it  should  be  noted  that  a  comparison 
of  vegetable  and  animal  proteins  shows  a  close  resemblance 
in  the  kind  of  building  stones  out  of  which  they  are  con- 
structed, although  the  proportions  are  unlike. 

1  There  is  no  popular  terminology  with  which  to  describe  these  com- 
pounds, that  are  known  only  to  the  chemist.  They  are  distinguished 
from  one  another  by  their  structure  and  chemical  relations,  and  are  stated 
in  this  connection  simply  to  show  that  important  structural  differences 
exist  between  the  proteins  named. 


Non-proteins  61 

Nitrogen  Compounds  that  are  Non-Proteins 

In  the  usual  method  for  determining  the  proteins  of  a 
food  by  multiplying  the  total  nitrogen  present  by  a  factor, 
there  is  included  in  the  calculation  nitrogen  that  does  not 
come  from  true  proteins,  but  from  compounds  that  possess 
physical  and  chemical  properties  greatly  removed  from 
those  which  characterize  albumin  and  other  true  proteins. 
Their  office  as  nutrients  is  also  less  comprehensive  than 
that  of  the  proteins. 

63.  Amides.  —  Certain  non-proteins  which  are  spoken  of 
under  the  term  amides  are  found  chiefly  in  plants.    As- 
paragine,   first   found  in  young  asparagus   shoots,   and 
glutamine,  found  in  germinating  pumpkin  seeds,  are  amides. 
They  are  soluble  in  water,  and  consequently  are  diffusible 
throughout  the  plant  tissues.     It  is  believed  that  they  are 
the  forms  in  which  the  nitrogen  compounds  of  the  plant 
are  transferred  from  one  part  to  another,  as,  for  instance, 
from  the  stem  to  the  seed.     It  has  generally  been  held 
that  these  bodies  are  more  abundant  in  young  plants  than 
in  mature.     A  larger  part  of  the  nitrogen  of  roots  and 
tubers    is    found    in    these   compounds   than   in   other 
foods,    the   proportion   in   grains   being   the   least,    and 
is  very  small  indeed.     Such  investigations  as  have  been 
conducted  point  to  the  conclusion  that  amides  are  not 
muscle-formers,  as  is  the  case  with  proteins.     This  is  a 
reason   for   regarding    the   protein   of   certain  vegetable 
foods  as  of  less  value  than  that  of  the  grains  and  grain 
products. 

64.  Extractives.  —  These  are  bodies  found  in  the  extract 
obtained  from  beef  with  cold  water.     After  the  albumin 


62  Principles  of  Human  Nutrition 

has  been  removed  from  such  an  extract  by  boiling,  these 
compounds,  known  as  creatin  and  creatinin,  chiefly  con- 
stitute the  nitrogenous  solids  that  remain.  The  food 
value  is  small,  if  anything,  for  they  appear  to  be  eliminated 
from  the  body  in  the  urine  without  change. 


CHAPTER   IV 

THE   COMPOUNDS   OF   HUMAN   NUTRITION, 
CONCLUDED 

CARBOHYDRATES,  ACIDS,   FATS,  AND  OILS 

MUCH  the  larger  proportion  of  the  dry  matter  of  human 
foods  consists  of  non-nitrogenous  material.  This  is  es- 
pecially true  of  the  cereal  grains.  While  these  nitrogen- 
free  compounds  are  not  regarded  by  many  as  fundamentally 
so  important  as  are  the  proteins,  in  quantity  they  unques- 
tionably occupy  the  first  rank.  The  activities  of  plant  life 
are  largely  devoted  lo  their  production,  and  their  use  by 
animal  life  is  correspondingly  extensive.  They  may 
properly  be  called  the  main  fuel  supply  of  the  animal 
world.  Other  nutrients  aid  in  maintaining  muscular 
force  and  animal  heat,  to  be  sure,  but  these  compounds 
are  the  principal  storehouse  of  that  sun-derived  energy 
which  furnishes  the  motive  power  exhibited  in  all  animal 
life.  They  are  also  important  in  other  ways,  for  they  fill 
a  necessary  office  in  the  formation  of  milk  and  in  the  fat- 
tening of  animals. 

65.  Elementary  composition.  —  The  compounds  of  this 
class  contain  only  three  elements,  —  carbon,  hydrogen, 
and  oxygen.  They  may  be  derived,  therefore,  wholly 
from  air  and  water,  and  they  constitute  that  portion  of 

63 


64 


Principles  of  Human  Nutrition 


human  foods  which    is    drawn  from  never   failing  and 
costless  sources  of  supply. 

The  elementary  composition  of  typical  nitrogen-free 
bodies  is  given  in  this  connection:  — 

TABLE   XVI 


CELLU- 
LOSE 

STARCH 

GLUCOSE 

SACCHA- 
ROSE 

STEARIN 

OLEIN 

Per  Cent 

Per  Cent 

Per  Cent 

Per  Cent 

Per  Cent 

Per  Cent 

Carbon 

44.4 

44.4 

40.0 

42.1 

76.7 

77.4 

Hydrogen 
Oxygen 

6.2 
49.4 

6.2 
49.4 

6.7 
53.3 

6.4 
51.5 

12.4 
11.0 

11.8 
10.8 

66.  Classification.  —  The  non-nitrogenous  compounds 
of  foods  are  usually  divided  into  two  main  classes,  viz. 
carbohydrates  and  similar  bodies  and  fats  and  oils.  The 
first  class  often  bears  the  name  nitrogen-free  extract,  but 
the  carbohydrates  are  its  principal  members.  The  second 
is  known  by  the  chemist  as  ether-extract,  because  ether  is 
used  to  extract  the  fats  or  oils  from  the  vegetable  sub- 
stances in  which  they  are  contained.  The  actual  fat 
obtained  from  vegetable  foods  is  always  less,  however, 
than  the  ether-extract,  because  the  ether  takes  into  solu- 
tion other  compounds  than  the  fats.  It  should  be  noted 
that  the  last  two  compounds  of  the  above  table,  which  are 
fats,  are  relatively  richer  in  carbon  and  hydrogen  and 
poorer  in  oxygen  than  the  other  compounds  mentioned, 
which  are  carbohydrates.  This  fact  has  an  important 
relation  to  nutritive  values. 


The  Carbohydrates  65 

The  Carbohydrates 

The  carbohydrates  as  a  class  make  up  a  large  proportion 
of  plant  substance  and  constitute  a  generous  share  of 
human  food.  While  the  compounds  of  this  class  are  not 
structurally  important  to  the  animal  organism,  they  fill 
a  large  place  in  the  animal  economy  in  maintaining  the 
vital  processes.  They  are  among  the  longest  known  and 
most  familiar  substances  that  are  now  used  as  food  by 
the  human  family. 

In  order  to  understand  the  carbohydrates  as  individual 
compounds  and  in  their  relations  to  each  other  and  to 
the  processes  of  nutrition,  it  is  necessary  to  consider  them, 
in  general  outlines  at  least,  from  the  standpoint  of  the 
chemist. 

The  term  carbohydrates,  like  the  term  protein,  is  collec- 
tive, and  includes  a  great  variety  of  compounds.  By  their 
common  names  we  know  them  as  celluloses,  starches, 
sugars,  gums,  vegetable  mucilages,  and  so  on.  Chemically 
we  distinguish  them  by  their  structure  and  by  their  re- 
lation to  one  another. 

The  Sugars 

When  considered  from  the  standpoint  of  efficiency,  the 
sugars  are  among  the  most  valuable  of  all  the  carbohydrates, 
although  in  quantity  they  are  less  important  than  the 
starches,  at  least  in  raw  food  materials. 

Unlike  starch,  they  are  found  in  solution  in  the  sap  of 
growing  plants.  It  is  probable  that  these  are  the  forms 
in  which  carbohydrate  material  is  transferred  from  one 
part  of  the  plant  to  another.  It  is  easy  to  see  that  some 
such  medium  of  exchange  is  necessary.  The  actual  pro- 


66  Principles  of  Human  Nutrition 

duction  of  new  vegetable  substance  takes  place  in  the 
leaves.  When,  therefore,  cell-walls  and  starch  grains 
are  to  be  constructed  in  the  stem  and  fruit,  the  building 
material  must  be  carried  from  the  leaves  to  these  parts 
in  forms  which  will  readily  pass  through  intervening  mem- 
branes. Excepting  certain  soluble  compounds,  closely 
related  to  starch,  the  sugars  appear  to  be  the  only  avail- 
able bodies  fitted  for  this  office. 

It  is  very  seldom  that  a  plant  contains  only  a  single 
sugar.  Generally  two  or  more  sugars  are  found  together. 
This  is  especially  the  case  in  the  corn  plant,  sorghum,  and 
the  fruits ;  and  the  proportions  of  each  depend  somewhat 
upon  the  stage  of  growth  of  the  plant. 

67.  Classification  of  sugars  according  to  structure.  — 
The  structure  of  certain  sugars  is  such  that  their  mole- 
cules cannot  be  divided  into  simpler  compounds  that  retain 
the  carbohydrate  character,  and  these  are  known  as  mono- 
saccharides.  To  this  class  belong  glucose  (grape  sugar) 
and  fructose  (fruit  sugar).  On  the  other  hand,  there  are 
a  large  number  of  carbohydrates,  one  molecule  of  which 
by  treatment  in  certain  ways  may  be  converted  into  two 
or  more  molecules  of  a  mono-  (  simple)  sugar.  For  instance, 
one  molecule  of  starch,  when  submitted  to  the  action  of 
an  acid  or  of  certain  ferments,  breaks  up  into  several 
molecules  of  glucose,  and  we  call  starch  a  poly-saccharide ; 
and  to  this  class  belong  sucrose  (cane  sugar),  maltose 
(malt  sugar),  lactose  (milk  sugar),  cellulose,  the  starches 
and  gums,  all  of  which  maybe  split  up  into  mono-  or  simple 
sugars.  The  poly-sugars  are  subdivided  into  di-,  tri-,  and 
so  on,  according  as  they  break  up  into  two,  three,  or  more 
molecules  of  a  simple  sugar. 


The  Simple  Sugars  67 

There  are  subdivisions  of  the  mono-sugars  also,  on  the 
basis  of  the  number  of  carbon  atoms  in  their  molecules, 
and  thus  we  have  the  names  diose,  triose,  tetrose,  pentose, 
hexose,  heptose,  etc.,  for  sugars  having  two,  three,  four, 
five,  six,  seven,  or  more  carbon  atoms  in  the  molecule.  It 
may  be  remarked  here  that  it  is  among  the  hexose  (six 
carbon)  sugars  or  their  multiples  that  we  find  the  carbo- 
hydrates most  important  to  human  nutrition. 

A.   The  Mono-saccharides  or  Simple  Sugars 

The  simple  sugars  that  are  most  important  in  human 
nutrition  are  dextrose  (grape  sugar),  levulose  (fruit  sugar), 
and  galactose  (from  milk  sugar).  These  are  hexose  (six 
carbon)  sugars.  The  pentoses  are  also  simple  sugars; 
but,  as  we  shall  see,  they  scarcely  occur  in  nature,  being 
obtained  chiefly  by  splitting  up  certain  gums. 

68.  Dextrose.  —  An  important  simple  sugar  is  dextrose 
or  grape  sugar,  or  what  is  known  in  the  market  as  glucose. 
Excepting  in  the  hands  of  the  chemist,  it  is  seldom  seen  as 
crystals,  although  these  appear  in  the  "  candying "  of 
honey  and  raisins.  Its  commercial  forms  are  as  a  con- 
stituent of  molasses  and  the  sirups.  Dextrose  is  found  in 
practically  the  same  plants  that  contain  saccharose,  such 
as  sorghum,  maize,  and  the  fruits.  So  far  as  known,  it  is 
always  associated  with  some  other  sugar.  On  account  of 
its  difficult  crystallization  and  a  lower  degree  of  sweetness, 
it  is  less  valuable  for  commercial  purposes  than  cane  sugar. 
That  which  appears  in  the  market  is  largely  made  from 
starch  by  the  use  of  an  acid,  and  it  is  often  utilised  for 
adulterating  the  more  costly  saccharose.  Many  sbem  to 
regard  glucose  as  a  substance  deleterious  to  health,  but  in 


68  Principles  of  Human  Nutrition 

consideration  of  the  fact  that,  in  digestion,  starch  and 
most  other  sugars  are  reduced  to  this  compound  before 
entering  the  circulation  of  the  animal,  this  view  does 
not  seem  to  be  sustained.  In  fact,  there  is  a  lack  of 
evidence  to  show  the  ill  effect  of  glucose  either  upon 
man  or  animals. 

69.  Levulose.  —  Another   simple   sugar   is   levulose  or 
fruit  sugar,  the  composition  of  which  is  identical  with  dex- 
trose, but  which  has  a  different  chemical  constitution. 
It  accompanies  dextrose,  and  is  found  in  some  fruits  in 
considerable  quantities,  and  especially  in  honey.     It  is  as 
sweet  as  cane  sugar,  but  does  not  form  crystals  with  the 
same  readiness. 

70.  Galactose.  —  This  is  obtained  by  a  cleavage  of  milk 
sugar  (see  later)  into  this  sugar  and  dextrose.     It  may  also 
be  obtained  from  certain  gums. 

71.  The  pentoses.  —  There  are  several  pentoses,  none 
of  which  occur  in  nature,  but  which  are  prepared  by  chem- 
ical methods  from  the  gums.     Thus,  from  gum  arabic  con- 
taining arabin,  arabinose  may  be  obtained,  and  from  zylin 
(wood  gum)  zylose  may  be  prepared.     Certain  of  these 
sugars  have  been  isolated  from  animal  compounds.     They 
also  have  been  found  to  appear  in  human  urine.     They 
are  of  great  importance  in  the  nutrition  of  herbivorous 
animals,  but  appear  in  human  food  only  to  a  limited  extent. 

B.   The  Di-saccharides 

These  carbohydrates  are  all  sugars  which  may  be  de- 
composed into  two  molecules  of  a  simple  sugar,  or  one 
molecule  of  each  of  two  simple  sugars.  They  are  only 
three  in  number,  —  saccharose  or  sucrose  (cane  sugar), 


The  Di-saccharides  69 

maltose  (malt  sugar) ,  and  lactose  (milk  sugar) .  When  acted 
upon  by  weak  acids  or  certain  ferments,  they  break  by 
cleavage  (hydrolysis)  as  follows  :  — 

Saccharose  +  water  =  dextrose  +  levulose 
Maltose  +  water  =  dextrose  +  dextrose 
Lactose  +  water  =  dextrose  +  galactose 

These  are  the  changes  that  occur  during  the  digestion 
of  food. 

72.  Saccharose.  —  The  most  important  of  these,  com- 
mercially considered,  is  saccharose,  which  is  the  ordinary 
crystallized  sugar  of  the  markets.  As  a  human  food  it 
is  widely  used,  is  especially  valuable,  and  its  manufacture 
and  sale  constitute  a  prominent  industry.  This  sugar 
is  obtained  mostly  from  two  plants,  sugar  cane  and  the 
sugar  beet.  It  also  exists  abundantly  in  sorghum,  pine- 
apples, carrots,  and  in  considerable  proportions  in  the 
stalk  of  ordinary  field  corn.-  The  first  spring  flow  of  sap 
in  one  species  of  maple  tree  is  richly  charged  with  it, 
and  in  a  few  states  large  quantities  of  maple  sirup  and 
sugar  are  manufactured. 

Saccharose  is  not  a  prominent  constituent  of  unmodified 
human  foods.  While  it  occurs  in  s^weet-potatoes  and  in 
roots,  and  perhaps  in  minute  proportions  in  certain  seeds, 
it  is  only  in  the  fresh  corn  plant,  sorghum,  pineapples,  and 
sugar  beets  that  it  constitutes  a  material  part  of  the  food 
substance. 

The  fruits  generally  contain  saccharose,  mixed  with 
other  sugars  and  organic  acids,  and  upon  the  relative  pro- 
portions of  these  compounds  depends  the  character  of  the 
fruit  as  to  acidity  or  sweetness. 


70  Principles  of  Human  Nutrition 

73.  Maltose.  —  A  sugar  that  is  intimately  related  to 
the  first  growth  which  occurs  in  the  germination  of  seeds  is 
maltose,  for  it  stands  as  an  intermediate  product  between 
the  store  of  starch  in  the  seed  and  the  new  tissues  of  the 
sprout.     The  solution  that  the  brewer  extracts  from  the 
malted  grains  contains  this  compound  as  the  principal 
ingredient,  and  through  succeeding  fermentations  in  the 
beer  vats  it  is  broken  up  into  alcohol  and  other  compounds. 
It  sustains  an  important  relation,  therefore,  to  the  produc- 
tion of  beers  and  other  alcoholic  liquors.     The  glucose 
sirups  found  in  the  markets  sometimes  contain  small  quan- 
tities of  this  sugar.     It  is  also  found  abundantly  in  the  in- 
testinal canal  during  the  digestion  of  food,  being  derived 
from  starch  and  other  carbohydrates  through  the  action  of 
ferments.     Maltose  is  similar  to  cane  sugar  in  ultimate 
composition,  but  not  in  constitution,  though  as  a  nutrient 
it  evidently  has  an  equivalent  value.     So  far  as  known, 
however,  it  does  not  appear  to  occur  in  material  quan- 
tities in  foods. 

74.  Lactose.  —  The  only  sugar  of  animal  origin  which  is 
abundant  in  farm  life  is  the  lactose  that  is  found  in  milk 
and  which  is  known  in  commerce  as  milk  sugar.     The  milk 
of  all  mammals  contains  sugar,  which  appears  to  be  the 
same  compound  with  every  species  so  far  investigated. 
When  they  are  fed  wholly  from  the  mother,  this  is  the  only 
carbohydrate  which  young  mammals  receive  in  their  food. 
The  average  proportion  of  sugar  in  the  milk  of  domestic 
animals  varies  from  three  to  six  parts  in  a  hundred,  cow's 
milk  containing  about  five  parts.     When  the  cream  is 
removed,  much  the  larger  part  of  sugar  remains  in  the 
skimmed  milk,  and  in  cheese-making  it  is  nearly  all  found 


The  Poly-saccharides  71 

in  the  whey,  from  which  the  milk  sugar  of  commerce  is 
obtained.  Very  soon  after  milk  is  drawn,  unless  it  is 
heated  to  the  point  of  sterilization,  or  is  treated  with  some 
antiseptic,  the  lactose  begins  to  diminish  in  quantity,  being 
converted  into  lactic  acid  through  the  action  of  what  is 
known  as  lactic  acid  organisms  (bacteria).  Sour  milk, 
therefore,  is  different  from  sweet  in  at  least  one  compound, 
and  this  change  causes  at  least  a  slight  modification  of  food 
value. 

C.   The  Poly-saccharides 

This  group  includes  a  large  number  of  carbohydrates 
that  may  be  considered  as  complexes  of  the  simple  sugars 
already  described.  Indeed,  they  make  up  the  principal 
bulk  of  the  carbohydrate  content  of  the  raw  materials 
from  which  human  food  is  prepared.  The  poly-saccharides 
may  be  divided  into  three  sub-groups,  the  starch  group, 
the  gum  and  vegetable  mucilage  group,  and  the  cellulose 
group,  the  first  being  the  one  of  greatest  importance  in 
human  nutrition. 

75.  The  Starches.  —  Starch  is  a  widely  distributed  and 
abundant  constituent  of  vegetable  tissue.  Food  plants, 
especially  those  most  used  by  the  human  family,  contain 
it  in  generous  proportions,  in  some  seeds  as  much  as  60 
or  70  per  cent  being  present.  Probably  only  water  and 
cellulose  are  more  abundant  in  the  vegetable  world. 

Starch  does  not  exist  in  solution  in  the  sap,  but  is  found 
in  the  interior  of  plant  cells  in  the  form  of  minute  grains 
which  have  a  shape,  size,  and  structure  characteristic  of 
the  seed  in  which  they  are  found.  Potato  starch  grains 
are  large,  about  3-^  of  an  inch  in  diameter,  and  are  kidney- 
shaped,  while  those  of  the  wheat  are  smaller,  about  TTTO 


72  Principles  of  Human  Nutrition 

of  an  inch  in  diameter,  and  resemble  in  outline  a  thick 
burning-glass.  Corn  starch  grains  are  angular,  being 
somewhat  six-sided,  and  those  of  other  seeds  show  marked 
and  specific  characteristics.  These  differences  in  size  and 
shape  furnish  the  most  important  means  of  detecting  adul- 
terations of  one  ground  grain  with  another,  as,  for  instance, 
when  corn  flour  is  mixed  with  wheat  flour. 

Unless  modified  by  some  chemical  change,  starch  is  not 
dissolved  by  water.  The  starch  grains  are  not  affected 
at  all  by  cold  water,  and,  in  hot  water,  at  first  only  swell 
and  burst.  Prolonged  treatment  with  hot  water  causes 
chemical  changes  to  more  soluble  substances.  For  this 
reason  the  simple  leaching  of  a  food  material  removes  no 
starch  by  solution.  At  the  same  time  th^  cooking  of  a 
ground  grain  so  breaks  up  and  liberates  the  starch  grains 
that  they  are  probably  acted  upon  more  promptly  by 
ferments  in  the  digestive  fluids. 

The  proportion  of  starch  in  plant  substances  used  for 
human  food  varies  greatly.  The  dry  matter  of  many 
seeds,  such  as  rice  and  the  cereal  grains,  wheat,  maize, 
barley,  or  oats,  is  largely  made  up  of  starch.  The 
same  is  true  of  potatoes  and  other  tubers.  Johnson 
quotes  the  following  figures  from  Dragendorff : 1  — 

TABLE    XVII 
AMOUNT  OP  STARCH  IN  DRY  MATTER 

PER  CENT  PER  CENT 

Wheat  kernel     ....     68.5    Peas 39.2 

Rye  kernel 67.0     Beans 39.6 

Oat  kernel 52.9     Flaxseed 28.4 

Barley  kernel     ....     65.0    Potato  tubers   ....  62.5 
1  "  How  Crops  Grow,"  p.  52. 


The  Poly-saccharides  73 

It  appears  that  in  grain  plants  starch  forms  most  abun- 
dantly during  the  later  development  of  the  seed.  At  the 
Maine  Station  none  could  be  found  in  very  immature 
field  corn  cut  August  15,  while  on  September  21  the  dry 
matter  of  the  whole  plant  on  which  the  kernels  had  ma- 
tured to  the  hardening  stage  contained  15.4  per  cent. 
In  general,  the  stem  and  leaves  of  forage  plants  are  poor 
in  starch. 

The  distribution  of  starch  in  seeds  is  worthy  of  note. 
The  grain  of  wheat  has  been  carefully  studied  in  this  par- 
ticular, and  it  is  found  that  this  body  does  not  normally 
exist"  in  the  seed  coatings,  this  tissue  consisting  largely 
of  mineral  matters,  proteins,  cellulose,  and  gums.  On 
the  contrary,  the  germ  and  the  interior  material  deposited 
around  it  are  rich  in  starch.  To  be  sure,  wheat  bran, 
which  is  now  very  largely  the  outer  seed  coats  of  the  grain, 
has  more  or  less,  but  this  is  due  to  imperfect  milling. 

Starch  is  an  important  commercial  article,  and  for  this 
purpose  is  mainly  obtained  from  corn  and  potatoes. 
Special  forms  of  starch  used  in  cookery  are  sago,  tapioca, 
and  arrowroot.  It  is  used  as  human  food,  as  a  source  of 
dextrin  and  in  other  ways.  By  treatment  with  an  acid, 
corn  starch  is  converted  into  the  glucose  of  our  markets, 
dextrin  and  maltose  being  intermediate  products. 

76.  Glycogen.  —  This  is  the  only  uncombined  carbo- 
hydrate found  in  the  animal  body  in  appreciable  quantity 
outside  the  forms  that  are  in  the  blood  circulation.  It  is 
sometimes  called  animal  starch.  It  is  a  white  powder, 
soluble  in  water,  and  may  be  extracted  in  small  amounts 
from  the  muscles  and  liver.  (See  p.  139.)  It  is  formed 
out  of  the  sugars  that  are  taken  into  the  circulation  from 


74  Principles  of  Human  Nutrition 

the  digestive  tract,  and,  as  we  shall  see,  is  a  reserve  store 
of  fuel  for  the  maintenance  of  muscular  energy,  and  in  this 
way  it  performs  a  very  important  office  in  nourishing  the 
animal  body.  It  was  formerly  believed  that  another 
carbohydrate  exists  in  muscle  called  inosite,  but  it  is  now 
known  that  this  substance  belongs  to  a  different  class  of 
compounds. 

77.  The   pentosans.  —  These  bodies   are  very  widely 
distributed  in  nature,  being  found  in  the  leaves,  stem, 
roots,  and  seeds  of  a  great  variety  of  plants,  in  algae  and 
in  beets  and  turnips.     Some  pentosans  are  known  as  gums, 
such  as  gum  ara.bic,  gum  tragacanth,  and  cherry  gum. 
Pentosans,  on   hydrolysis,  yield    pentose  sugars,   among 
which  are    arabinose  and  zylose.     These  gum-like  sub- 
stances exist  in  such  human  foods  as  beets  and  turnips, 
spinach,  cabbage,  and  other  vegetables  that  serve  more 
or  less  as  human  food. 

78.  Galactans,   mannans,  levulans,   dextrans.  —  These 
are  compounds  of  little  importance  in  human  nutrition 
that  are  more  or  less  associated  in  the  framework  of  a  great 
variety  of  plants  or  parts  of  plants,  including  seeds,  beets, 
and    turnips,    tubers    and    bulbs,   algae,    lichens,    molds, 
and  the  wood  and  bark  of  many  species  of  trees.     On 
hydrolysis  they  yield  galactose,  mannose,   levulose,   and 
dextrose,  respectively. 

Together  with  the  pentosans  these  compounds  make  up 
the  least  valuable  part  of  certain  vegetable  foods. 

79.  The  pectin  bodies. — Another  class  of  compounds 
much  like  the  gums,  and  perhaps  related  to  them  chem- 
ically, is  the  pectin  bodies.     Some  of  these  substances  are 
gelatinous  in  appearance.     The  jellying  of  fruits,  such  as 


The  Poly-saccharides  75 

apples  and  currants,  is  made  possible  by  their  presence. 
They  exist  in  greater  abundance  in  unripe  fruit  than  in 
the  ripe,  consequently  the  former  is  selected  for  jelly- 
making.  When  such  fruits  are  cooked,  the  pectin  which 
they  contain  takes  up  water  chemically  and  is  transformed 
into  a  gelatinous  substance,  and  the  secret  of  jelly-making 
is  in  stopping  the  cooking  process  before  the  chemical  trans- 
formations have  passed  beyond  a  certain  point.  Muci- 
lages not  greatly  unlike  the  gums  and  pectins  exist  in  cer- 
tain seeds  and  roots,  the  most  notable  instance  being 
flaxseed. 

80.  Dextrin,  which  is  sometimes  spoken  of  as  a  gum, 
is  made  by  heating  starch  to  about  200°  C.    It  may  also  be 
produced  by  treating  starch  with  a  dilute  acid.     Dextrin 
is  undoubtedly  formed  on  the  outer  part  of  the  loaf  when 
wheat  bread  is  baked.     It  is  soluble  in  water. 

81.  Cellulose.  —  This  is  found  in  the  tough  or  woody 
portion  of  plant  tissue.     In  tables  of  food  analyses  we  find 
the  term  crude  fiber,  which  consists  largely  of  cellulose,  a 
familiar  example  of  which  in  a  nearly  pure  form  is  the 
cotton  fiber  used  in  making  cloth.     Crude  fiber  is  separated 
from  associated  compounds  by  the  successive  treatment 
of  vegetable  substance  with  weak  acids  and  alkalies,  and 
as  so  determined  is  sometimes  improperly  taken  to  repre- 
sent the  amount  of  cellulose  in  a  plant.     While  crude  fiber 
is  mainly  cellulose,  it  contains  a  small  proportion  of  other 
compounds,  and,  besides,  more  or  less  cellulose  is  dissolved 
by  the  acid  and  alkali  treatment,  so  that  the  percentages 
of  crude  fiber  given  in  food  tables  only  approximately 
measure  the  cellulose  present. 

All  plant  tissue  is  made  up  of  cells,  the  walls  of  which 


76  Principles  of  Human  Nutrition 

are  chiefly  or  wholly  cellulose.  It  is  this  substance  out  of 
which  is  built  the  framework  of  the  plant,  and  which  gives 
toughness  and  rigidity  to  certain  of  its  parts.  The  more 
of  this  plant  tissue  contains,  the  more  tenacious  it  is,  other 
things  being  equal,  and  the  more  difficult  of  mastication. 

The  proportions  of  cellulose  in  the  different  parts  of  a 
plant  are  greatly  unlike.  It  is  usually  most  abundant 
in  the  stem,  with  less  in  the  foliage  and  least  in  the  fruit. 
With  vegetables  like  potatoes  and  turnips,  the  leaves  are 
much  richer  in  fiber  than  the  tubers  or  roots,  which  contain 
a  comparatively  small  proportion.  Of  the  grains  or  seeds 
considerable  is  present  in  the  outer  coatings,  while  but  little 
is  found  in  the  interior.  Considering  human  foods  of  plant 
origin,  we  find  that  vegetables  such  as  celery,  lettuce,  beets, 
and  turnips  are  relatively  rich  in  crude  fiber,  while  tubers, 
flours,  and  meals  contain  only  small  amounts.  In  certain 
by-products  from  the  grains,  like  bran,  which  is  made  up 
mostly  of  the  seed  coatings,  fiber  is  present  in  fairly  large 
proportions,  while  in  flour  derived  from  the  inner  parts  of 
the  grain  the  percentage  is  almost  negligible. 

The  stage  of  growth  at  which  a  plant  is  used  for  food 
purposes  has  a  marked  influence  upon  the  proportion  of 
crude  fiber.  In  young,  actively  growing  vegetable  tissue, 
the  cell-walls  are  thin,  but,  as  the  plant  increases  in  age, 
these  thicken  chiefly  through  the  deposition  of  cellulose. 
In  general,  the  toughness  and  hardness  of  mature  plants, 
as  compared  with  young,  is  due  to  the  increased  proportion 
of  woody  fiber,  although  the  decrease  in  the  relative 
amount  of  water  in  the  tissues  and  the  deposition  of  other 
substances  have  more  or  less  effect.  The  rapid  toughen- 
ing of  young  asparagus  tips  and  the  tenderness  of  young 
beets  as  compared  with  old  ones  are  cases  in  point. 


The  Adds;  Fats  and  Oils  77 

The  Acids 

Other  substances  besides  those  of  a  carbohydrate  char- 
acter are  included  in  the  nitrogen-free  extract.  Chief 
among  these  are  the  organic  acids,  compounds  which  are 
found  mostly  in  the  fruits,  although  they  appear  in  certain 
fermented  products,  such  as  sauerkraut  and  sour  milk. 
The  most  important  and  well  known  of  these  are  acetic 
acid,  found  in  vinegar,  citric  acid  in  lemons,  lactic  acid  in 
sour  milk,  malic  acid  in  many,  fruits,  such  as  currants  and 
apples,  and  oxalic  acid  in  rhubarb.  Probably  these  acids 
are  sometimes  free,  but  the  trend  of  opinion  is  that  gen- 
erally they  are  united  with  potassium  or  some  other 
base,  forming  an  acid  salt.  Excepting  the  fruits,  only 
fermented  foods  contain  acids  to  an  appreciable  extent. 
When  milk  sours,  the  sugar  in  it  is  changed  to  lactic  acid 
under  the  influence  of  a  ferment.  In  sauerkraut,  various 
acids  are  formed  at  the  expense  of  the  carbohydrates  that 
are  in  the  material  which  is  subjected  to  fermentation. 

Fats  and  Oils 

The  fats  or  oils  are  compounds  greatly  important  in  the 
nutrition  of  man.  There  are  many  individual  fats,  those 
known  in  common  life  as  tallow,  lard,  butter,  and  oils,  such 
as  linseed  and  cottonseed  oils,  being  mixtures  of  three  or 
more  of  these. 

When  any  finely  ground  foodstuff,  either  vegetable  or 
animal,  is  submitted  to  the  leaching  action  of  ether,  chloro- 
form, or  certain  other  liquids,  several  compounds  are  taken 
into  solution,  the  main  and  important  ones  being  fats  or 
oils.  These  bodies  make  up  the  chief  portion  of  such  an 


78  Principles  of  Human  Nutrition 

extract  from  seeds,  while  material  so  derived  from  other 
vegetable  materials  also  contains  a  considerable  amount 
of  wax,  chlorophyll,  and  other  substances.  Tables  that 
show  the  composition  of  foods  have  a  column  which  is 
sometimes  designated  "  ether-extract,"  and  sometimes 
"  fats  or  oils."  The  former  is  the  more  accurate  term, 
because  the  compounds  which  it  is  the  intention  to  describe 
are  often  no  more  than  half  fats  or  oils.  The  real  value  of 
the  "  ether-extract  "  from  different  foods  is  partly  deter- 
mined, therefore,  by  its  source.  When  it  is  all  oil,  or 
nearly  so,  it  is  worth  much  more  for  use  by  the  animal 
than  when  it  is  made  up  to  quite  an  extent  of  other 
bodies. 

82.  Fats  in  grains  and  seeds.  —  The  proportions  of  fat 
or  oil  in  foods  vary  within  wide  limits.  In  general,  seeds 
and  their  by-products  contain  more  than  the  stem  and 
leaves,  the  differences  in  the  percentages  of  actual  oil  being 
greater  than  is  indicated  by  the  ether-extract.  But  little 
is  found  in  the  dry  matter  of  roots  and  tubers.  Among 
the  cereal  grains  and  other  more  common  farm  seeds,  corn 
and  oats  show  the  largest  amounts,  the  proportion  in  dry 
matter  being  from  five  to  six  in  one  hundred,  while  wheat, 
barley,  rye,  peas,  and  rice  contain  much  smaller  percen- 
tages, wheat  having  about  2  per  cent,  and  rice  sometimes 
not  over  one-fifth  of  1  per  cent.  Agricultural  seeds  that 
are  especially  oleaginous  are  cottonseed,  flaxseed,  sun- 
flower seeds,  and  the  seeds  of  many  species  belonging  to 
the  mustard  family,  such  as  rape.  Peanuts,  coconuts, 
and  palm  nuts  are  also  very  rich  in  oil.  The  average  per- 
centages in  these  seeds  and  nuts  are  approximately  as 
given  below :  — 


The  Fats  and  Oils  79 

TABLE    XVIII 

OIL  IN  CERTAIN  SEEDS 

PER  CENT  PER  CENT 

Linseed  ....     ...     34  Peanuts      ......     46 

Cottonseed 30     Coconuts         67 

Sunflower  seed      ....     32     Palm  nuts 49 

Rape  seed 42     Poppy  seed 41 

Mustard  seed  .     .     ...     32 

The  oils  from  all  the  above  are  important  commercial 
products,  being  used  in  a  great  variety  of  ways  in  human 
foods  and  in  the  arts.  In  many  cases,  the  refuse  from  this 
extraction  goes  back  to  the  farm  as  food  for  cattle.  This 
is  especially  true  of  linseed  and  cottonseed. 

83.  Fat-rich  foods: — Certain  of  the  raw  materials  used 
in  the  human  dietary  are  practically  all  fat  or  oil,  such  as 
lard,  butter,  and  the  salad  oils.     Meats  such  as  pork,  beef, 
and  mutton  are  rich  in  fats,  the  proportion  depending 
greatly  on  the  condition  of  the  animal  from  which  the  meat 
comes. 

84.  Nature  and  kinds  of  fats.  —  The  vegetable  and  ani- 
mal fats  and  oils  may,  for  convenience'  sake,  be  discussed 
in  two  divisions,  the  neutral  fats  or  glycerides  and  the  fatty 
acids.     The  neutral  fats  are  combinations  of  the  fatty 
acids  with  glycerin.     When,  for  instance,  lard  is  treated 
at  a  high  temperature  with  the  alkalies,  potash,  and  soda, 
glycerin  is  set  free,  and  an  alkali  takes  its  place  in  a  union 
with  the  fatty  acids.     This  is  the  chemical  change  which 
occurs  in  soap-making.     There  are  several  of  these  neutral 
fats,  the  ones  most  prominent  and  important  in  agriculture 


80  Principles  of  Human  Nutrition 

being  those  abundant  in  butter  and  in  the  body  fats  of 
animals;  viz.  butyrin,  caproin,  caprylin,  caprin,  laurin, 
myristin,  olein,  palmatin,  and  stearin,  the  last  three  being 
the  most  abundant  and  important  in  human  foods.  Buty- 
rin is  a  combination  of  butyric  acid  and  glycerin,  stearin 
of  stearic  acid  and  glycerin,  and  so  on.  Because  these 
are  combinations  of  three  molecules  of  a  fatty  acid  radical 
with  one  of  glycerin,  they  are  sometimes  named  tri- 
stearin,  tri-palmatin,  and  tri-olein,  and  so  on.  Some 
single  fats  (glycerides)  are  compounds  of  two  or  three 
fatty  acid  radicles  united  with  glycerin  in  the  same 
molecule.  As  glycerin  is  an  alcohol,  and  as  combinations 
of  an  alcohol  and  acids  are  ethers,  the  neutral  fats  are 
really  ethers  (esters),  although  they  differ  greatly  from  our 
conceptions  of  an  ether,  which  is  gained  from  ethyl  ether 
or  the  ether  of  drug  stores. 

85.  Physical  properties.  —  These  individual  fats  possess 
greatly  unlike  physical  properties.  They  are  all  soluble 
in  benzine,  chloroform,  and  ether,  and  insoluble  in  water. 
At  the  ordinary  temperature  of  a  room,  some  are  liquid 
and  some  are  solid,  olein  belonging  to  the  former  class,  and 
palmatin  and  stearin  to  the  latter.  It  is  a  matter  of  com- 
mon observation  that  butter,  lard,  and  tallow  differ  in 
hardness  at  a  given  temperature,  and  by  the  use  of  a  ther- 
mometer it  may  easily  be  discovered  that  their  melting 
points  are  not  the  same.  As  these  animal  fats  are  in  all 
cases  chiefly  mixtures  of  olein,  palmatin,  and  stearin,  stearin 
and  palmatin  being  a  solid  at  ordinary  temperatures,  and 
olein  a  liquid  at  anything  above  the  freezing  point,  it  is 
evident  that  the  relative  proportions  of  these  compounds 
will  affect  the  ease  of  melting  and  the  hardness  of  the  mix- 


The  Fats  and  Oils  81 

tures  of  which  they  are  a  part.  Stearin  melts  at  71.7°  C. 
and  palmatin  at  62°  C.  Tallow,  having  more  stearin  than 
lard  and  butter,  and  less  olein,  is  consequently  much  more 
solid  on  a  hot  day. 

The  composition  and  physical  properties  of  the  fat  from 
a  beef  animal  seem  to  vary  according  to  the  age  of  the  ani- 
mal and  the  locality  of  the  body  from  which  the  fat  is  taken. 
Fat  from  an  old  animal  melts  at  a  lower  temperature  than 
that  from  a  young  animal,  and  the  same  is  true  of  fat  taken 
from  the  outside  of  the  body  as  compared  with  that  taken 
from  the  inside.  Fat  from  herbivora  is  in  general  harder 
than  that  from  carnivora. 

86.  Milk  fat.  —  Milk  fat  contains  not  only  the  three 
principal  fats,  but  also  the  others  mentioned,  butyrin,  cap- 
roin,  caprylin,  caprin,  laurin,  and  myristin,in  small  propor- 
tions, and  these  latter  tend  to  give  butter  certain  properties 
that  distinguish  it  from  the  other  animal  fats,  which  are 
almost  wholly  palmatin,  olein,  and  stearin.    These  special 
butter  fats  are  liquid  at  ordinary  temperatures.     Doubt- 
less the  flavor,  texture,  and  resistance  of  butter  to  the  effects 
of  heat  are  much  influenced  by  the  proportions  of  the  numer- 
ous fats  it  contains,  but  there  is  much  connected  with  this 
subject  of  which  we  are  still  ignorant. 

87.  Fatty  acids.  —  Free,   fatty  acids  exist  in  nature. 
They  are  not  found  in  butter,  lard,  and  tallow  unless  these 
substances  have  undergone  fermentations,  or,  as  we  say, 
have  become  rancid.     The  characteristic  flavor  of  strong 
butter  is  due  to  free  butyric  acid,  which,  because  of  fer- 
mentations, has  parted  from   the   glycerin  with  which  it 
was  originally  combined  in  the  milk.     In  plant  oils,  on  the 
other  hand,  are  found  considerable  proportions  of  the  free 


82 


Principles  of  Human  Nutrition 


fatty  acids,  some  of  which  have  not  been  discovered  so  far 
in  animal  fats,  either  free  or  uncombined. 

88.  Ether-extracts.  —  Perhaps  no  one  has  studied  plant 
oils  more  thoroughly  than  Stellwaag,  who  investigated  the 
ingredients  of  the  ether-  and  benzine-extracts  from  plants. 
His  results  show  that  not  only  do  these  extracts  include 
substances  which  are  not  fats,  but  that  a  considerable  pro- 
portion of  free,  fatty  acids  is  always  present,  sometimes 
in  quantities  exceeding  the  neutral  fats :  — 


TABLE   XVIII  a 

COMPOSITION  OF  ETHER-EXTRACTS  (PER  CENT) 


NEUTRAL 
FATS 

FBEE  FATTY 
ACIDS 

MATERIAL  NOT 
SAPONIFIABLE 

Potatoes  
Beets  

16.3 
230 

56.9 
353 

10.9 
10  7 

Maize,  kernel  .... 
Barley  
Oats 

88.7 
73.0 
61  6 

6.7 
14.0 
276 

3.7 
6.1 
2  4 

It  appears,  as  before  stated,  that  ether-extract,  especially 
that  from  vegetables,  may  consist,  to  some  extent,  of  ma- 
terials which  should  not  be  classed  among  the  fats.  The 
extracts  from  the  grains  proved  to  be  nearly  all  oil.  More- 
over, the  grain  oils  were  made  up  principally  of  glycerides, 
and  those  from  potatoes  and  beets  consisted  largely  of 
free,  fatty  acids. 

89.  Lecithins.  —  There  is  a  group  of  bodies  closely 
related  to  the  fats,  which  are  often  called  the  phosphorized 
fats.  Reference  is  made  to  the  lecithins.  It  has  pre- 


The  Fats  and  Oils  83 

viously  been  stated  that  neutral  fats  are  combinations  of 
fatty  acids  and  glycerin  (glycerol).  Lecithins  are  com- 
pounds in  which  one  of  the  radicals  of  a  fatty  acid  is 
replaced  by  a  compound  of  phosphoric  acid.  They  are 
widely  distributed  in  nature.  They  appear  to  be  an  active 
component  of  every  cell,  both  of  vegetable  and  animal 
tissue,  and  they  are  especially  abundant  in  seeds,  in  the 
nerve  system,  in  fish,  eggs,  and  in  the  yolk  of  eggs.  These 
bodies  evidently  fill  an  important  place  in  plant  and  animal 
nutrition.  These  are  good  theoretical  reasons  for  suggest- 
ing that  lecithins  serve  as  a  stepping  stone  to  the  synthesis 
of  the  nucleoproteins.  In  digestion  they  behave  like 
the  true  fats. 


CHAPTER   V 
THE   DIGESTION   OF  FOOD 

WE  have  accepted  so  far  without  discussion  the  almost 
self-evident  fact  that  the  food  is  the  immediate  source  of 
the  substance  and  energy  of  the  animal  body.  It  now 
remains  for  us  to  consider  the  way  in  which  nutrition  is 
accomplished.  The  first  step  in  this  direction  is  the  diges- 
tion of  food.  It  is  necessary  for  food  ingredients  to  be 
placed  in  such  relations  to  the  animal  organism  that  they 
are  available  for  use.  This  involves  both  condition  and 
location.  The  various  nutrients  in  the  exercise  of  their 
several  functions  must  be  generally  distributed  to  all  the 
interior  parts  of  the  animal  body.  It  is  obvious  that  bread 
and  meat  as  such  cannot  be  so  distributed,  and  so  their 
compounds  must,  in  part  at  least,  be  brought  into  soluble 
and  diffusible  condition,  in  order  that  they  may  pass 
through  the  membranous  lining  which  separates  the  blood 
vessels  and  other  vascular  bodies  from  the  cavity  of  the 
alimentary  canal.  * 

90.  Digestion  and  assimilation.  —  In  discussing  physio- 
logical relations  of  food,  two  terms  are  employed :  viz., 
digestion  and  assimilation.  Digestion  refers  to  the  prepa- 
ration of  food  compounds  for  use,  by  rendering  them  soluble 
and  diffusible,  —  changes  which  are  accomplished  in  what 
we  call  the  alimentary  canal,  a  passage  that  begins  with 

84 


Changes  through  Digestion  85 

the  mouth,  includes  the  stomach  and  intestines,  and  ends 
with  the  anus.  Assimilation  signifies  the  appropriation 
of  nutrients,  after  digestion,  to  the  maintenance  of  the 
vital  processes  and  to  the  building  of  flesh  and  bone, — pro- 
cesses taking  place  in  the  tissues,  to  which  the  nutritive 
substances  are  conveyed  by  the  blood.  The  two  terms 
are  entirely  distinct  in  meaning,  although  they  are  confused 
in  popular  speech. 

91.  General  changes  in  food  through  digestion.  —  In 
digestion,  food  undergoes  both  mechanical  and  chemical 
changes.  It  is  masticated,  that  is,  ground  into  finer  parti- 
cles, after  which,  in  its  passage  along  the  alimentary  canal, 
it  comes  in  contact  with  several  juices  which  profoundly 
modify  it  chemically.  That  portion  of  it  which  is  rendered 
diffusible  is  absorbed  by  certain  vessels  that  are  embedded 
in  the  walls  of  the  stomach  and  intestines,  and  is  conveyed 
into  the  blood.  The  insoluble  part  passes  on  and  is  re- 
jected by  the  animal  as  worthless  material,  and  constitutes 
the  solid  excrement  or  feces.  The  forms  in  which  the 
nutrients  are  conveyed  into  the  circulation  are  believed  to 
be  the  following:  The  proteins,  previous  to  absorption, 
into  the  blood,  are  converted  into  soluble  bodies,  proteoses 
and  peptones,  or  mainly  into  simpler  nitrogen  compounds^ 
resulting  from  a  more  extensive  cleavage,  or  more  probably 
into  all  these  forms ;  the  carbohydrates  enter  the  blood  as 
sugars,  chiefly  as  dextrose.  The  fats  are  changed  into 
a  finely  divided  form  either  as  such  or  as  fatty  acids 
and  soaps.  The  function  of  digestion  is  to  transform 
the  various  nutrients  into  these  forms.  A  study  of  di- 
gestion includes,  then,  a  knowledge  of  mastication,  of 
the  sources,  nature,  and  functions  of  the  several  diges- 


86  Principles  of  Human  Nutrition 

live  juices,  and  a  consideration  of  the  various  conditions 
affecting  the  extent  and  rapidity  of  digestive  action. 

A.   FERMENTS 

The  changes  involved  in  rendering  food  compounds 
soluble  are  intimately  connected  with  a  class  of  bodies 
known  as  ferments,  to  which  brief  reference  has  already 
been  made,  and  it  seems  necessary  before  proceeding  to 
a  consideration  of  digestion  as  a  process  to  learn  something 
of  the  nature  and  functions  of  these  agents,  which  are 
actively  and  essentially  present  in  the  digestive  tract. 

A  ferment  may  be  defined  in  a  general  way  as  something 
which  causes  fermentation;  in  other  words,  the  decom- 
position of  certain  vegetable  or  animal  compounds  with 
which  it  comes  in  contact  under  favorable  conditions. 
Ferments  have  been  classified  into  two  kinds,  organized 
and  unorganized.  The  so-called  organized  ferments  are 
low,  microscopic  forms  of  vegetable  life,  generally  single- 
celled  plants.  Those  known  as  unorganized  ferments  are 
not  living  organisms,  but  are  simply  chemical  compounds. 

92.  Organized  ferments.  —  When  milk  is  allowed  to 
remain  in  a  warm  room  for  several  hours,  it  becomes  sour. 
An  examination  of  it  chemically  shows  that  its  sugar  has 
largely  or  wholly  disappeared  and  has  been  replaced  by 
an  acid.  A  study  of  the  milk  with  the  microscope,  before 
and  after  souring,  reveals  the  fact  that  there  has  been  a 
marvelous  increase  in  it  of  single-celled  organisms  or  plants. 
The  presence  of  this  form  of  life  is  regarded  as  the  cause  of 
the  change  of  the  sugar  into  lactic  acid.  We  have  here  a 
so-called  lactic  acid  ferment,  which  may  typify  the  or- 
ganized ferments  known  as  bacteria.  Numerous  other 


Organized  Ferments  87 

fermentations  of  the  same  general  kind  are  common  to 
everyday  experience.  The  changes  in  the  cider  barrel 
and  the  wine  cask,  the  spoiling  of  canned  fruits  and  vege- 
tables, and  the  heating  of  hay  and  grain  are  illustrations 
of  what  is  accomplished  by  these  minute  organisms. 

Bacteria  that  cause  disease  and  which  multiply  in  the 
organs,  and  other  tissues  of  the  animal  body,  may  also  be 
properly  called  ferments,  because  in  their  growth  new 
compounds,  toxins l  perhaps,  are  formed  which  are  as  truly 
fermentative  by-products  as  the  carbonic  acid  and  alcohol 
of  cider  and  beer  making.  As  this  subject  viewed  on  its 
pathogenic  side  is  not  important  in  this  connection,  we 
need  to  study  organized  ferments  only  so  far  as  they  relate 
to  the  preservation  of  foods  and  to  changes  in  the '  ali- 
mentary canal.  We  shall  be  best  equipped  for  controlling 
ferments  and  preventing  their  destructive  action  if  we 
know  what  they  are,  and  understand  the  general  condi- 
tions under  which  they  thrive.  We  should  also  know  how, 
and  to  what  extent,  their  action  occasions  harm. 

93.  Structure.  Distribution.  —  The  organized  ferments 
are  classed  in  the  vegetable  kingdom.  As  a  rule, 
each  individual  plant  is  a  single  cell,  varying  in  shape 
and  so  minute  as  to  be  invisible  to  the  unaided  sight. 
It  corresponds  in  its  general  structure  to  the  cells 
which  make  up  the  tissues  of  the  higher  vegetable 
species,  i.e.,  it  consists  of  a  cell-wall  inside  of  which  are 
protoplasm  and  other  forms  of  living  matter.  These  or- 
ganisms are  distributed  everywhere,  —  in  the  air,  in  the 
soil,  on  surfaces  of  plants,  and  in  the  bodies  of  animals. 

1  Poisonous  albuminous  bodies,  produced  by  bacterial  action  ;  as,  for 
instance,  in  typhoid  fever,  diphtheria,  tetanus,  and  other  diseases. 


88  Principles  of  Human  Nutrition 

Whenever  the  right  opportunity  offers  itself,  they  multiply 
and  bring  about  all  the  results  attendant  upon  their 
growth. 

94.  Conditions  of    growth.  —  The  conditions  essential 
to  their  development  are  the  proper  degree  of  moisture 
and    temperature    and    the    necessary    food    materials. 
Thoroughly   dry   animal    and    vegetable    substances    do 
not  ferment.     Flour  and  meal  that  have  been  dried  to 
a  water  content  of  10  per  cent  will  keep  a  long  time 
without    loss  from  fermentative  changes.     The  heat  in 
a  bin  of  new  grain,  with  its  subsequent  musty  condition, 
is  due  to  the  fermentations  that  are  made  possible  through 
the  presence  of  considerable  moisture.     Thorough  drying 
is  a 'preventive  of  destructive  fermentations. 

There  is  a  temperature  at  which  each  vegetable  fer- 
ment thrives  best,  and  there  are  limits  of  temperature 
outside  of  which  the  growth  of  these  forms  of  life  does  not 
occur,  or  is  very  slight.  Numerous  species  thrive  between 
75°  and  100°  F.  Fermentable  materials  like  fruit  and 
meat  at  the  freezing  point  or  below  are  not  subject  to 
fermentations.  The  boiling  point  of  water  kills  most 
bacteria,  and  temperatures  above  150°  F.  retard  or  entirely 
prevent  their  growth. 

95.  Results    of    fermentations.  —  Like    all    life,    these 
organisms    must    have    food.      Many    species    find    this 
in  acceptable  forms  in  vegetable  and  animal  products. 
Because    these    products    generally    contain    the    sugar, 
proteins,  and  mineral   compounds  which  nourish  bacte- 
ria, many  of  them  are  the  prey  of  ferments  under  proper 
conditions  of    moisture  and    heat.      The  prevention   of 
fermentation  in  foods  is  desirable  because  it  occasions 


Organized  Ferments  89 

a  loss  of  nutritive  value  and  often  produces  undesirable 
flavors.  The  loss  becomes  evident  when  we  consider  the 
nature  of  the  chemical  changes  that  occur.  For  instance, 
when  sugar  of  cider  is  broken  up  through  the  influence  of 
a  bacterium,  the  carbon  dioxid  and  alcohol  are  formed 
through  the  appropriation  of  free  oxygen.  This  means 
that  combustion  occurs,  causing  the  liberation  of  energy 
which  otherwise  would  have  been  available  if  the  sugar 
had  been  taken  as  food.  Many  fermentations  involve 
oxidation,  all  of  which  are  destructive  of  food  value. 

96.  Manner  of  action.  —  Several  theories  have  been 
.advanced  to  account  for  the  action  of  the  organized 
ferments.  One  is  that  these  little  plants  use  sugar 
and  other  compounds  as  food,  deriving  energy  and 
growth  therefrom,  the  carbonic  acid,  alcohol,  and  other 
new  bodies  being  the'  by-products  of  this  use.  Another 
is  that  these  organisms  produce  an  unorganized  fer- 
ment which  brings  about  the  fermentative  changes,  and 
their  action  is  therefore  indirect.  Indeed,  it  seems  to 
be  definitely  proved  that  it  is  possible  to  separate  from 
the  cells  of  the  yeast  plant  a  ferment  that,  in  the  ab- 
sence of  the  yeast  plant  itself,  converts  sugar  into  carbon 
dioxid  and  alcohol.  This  shows  that  the  effective  agent 
in  bacterial  fermentations  is,  after  all,  a  chemical  substance, 
or  an  unorganized  ferment.  These  later  discoveries  tend 
to  remove  the  distinction  that  has  been  made  between  or- 
ganized and  unorganized  ferments.  Whatever  may  be  the 
real  explanation  of  the  changes  that  occur,  fermentations 
due  to  plant  growth  are  among  the  most  useful  agencies  with 
which  we  deal,  and  may  be  the  most  harmful.  The  yeast 
plant  is  an  organized  ferment,  and  in  bread-making  it  is 


90  Principles  of  Human  Nutrition 

useful,  but  the  putrefaction  of  meats  under  the  influence 
of  another  ferment  causes  loss. 

The  digestive  tract  of  man  is  inhabited  by  countless 
numbers  of  bacteria.  These  are  found  to  some  extent 
in  the  stomach,  but  most  abundantly  in  the  intestines, 
especially  in  the  colon.  The  two  main  types  in  which 
we  are  interested  in  their  relation  to  digestion  are  the 
fermentative  or  those  that  attack  the  carbohydrates, 
especially  the  sugars,  and  the  putrefactive,  or  those  that 
cause  decomposition  of  the  proteins.  The  former  are 
most  active  in  the  stomach  and  when  carbohydrate- 
bearing  foods,  especially  sweets,  are  eaten  in  excess,  or 
for  any  reason  the  food  remains  an  abnormally  long 
time  in  the  stomach,  as  when  the  organ  is  weak 
muscularly,  an  uncomfortable,  and  sometimes  danger- 
ous, evolution  of  acids  and  gases  occurs.  As  the  pres- 
ence of  hydrochloric  acid  tends  to  inhibit  the  growth  of 
these  organisms,  an  insufficient  secretion  of  gastric 
juice  gives  an  opportunity  for  stomach  fermentations 
that  would  not  occur  under  normal  conditions. 

The  putrefactive  fermentations,  which  are  favored  by 
a  heavy  meat  diet,  begin  in  the  lower  part  of  the  small 
intestine  and  reach  their  maximum  in  the  colon.  In 
excessive  meat  eating,  particularly  when  the  food 
residues  remain  for  an  unusually  long  time  in  the  in- 
testines, putrefactive  products  may  be  evolved  to  a 
harmful  extent,  sometimes  causing  serious  results.  But 
with  healthy  individuals  under  proper  conditions  of  diet 
the  bacteria  present  in  the  digestive  tract  are  at  least 
not  harmful,  and  according  to  older  views,  now  more 
or  less  discredited,  are  useful  adjuncts  of  digestion. 


Unorganized  Ferments  91 

97.  Unorganized  ferments.  —  There  is  another  class 
of  ferments  which  is  termed  unorganized,  and  to  which 
the  general  name  enzym  is  given.  These  are  the  ferments 
especially  important  in  digestion.  They  are  merely  chem- 
ical compounds  which  produce  a  peculiar  effect  upon  cer- 
tain bodies  with  which  they  come  in  contact.  If  a  thin 
piece  of  lean  beef  be  suspended  in  an  extract  from  the 
mucous  lining  of  a  pig's  stomach,  to  which  has  been  added 
a  small  proportion  of  hydrochloric  acid,  the  liquid  being 
kept  at  about  98°  F.,  the  beef  will  soon  begin  to  soften, 
afterwards  swell  to  a  more  or  less  jelly-like  condition,  and 
finally  dissolve.  The  same  general  result  would  occur 
with  fish,  blood  fibrin,  or  the  coagulated  white  of  an  egg. 
When  starch,  which  is  not  affected  by  pure,  warm  water, 
is  placed  in  a  warm  water  solution  of  crushed  malt,  it  soon 
dissolves,  leaving  a  comparatively  clear  liquid.  A  chem- 
ical examination  of  these  preparations  will  reveal  the  fact 
that  the  compounds  of  the  meat  are  present  in  solution 
in  somewhat  modified  forms,  and  that  the  starch  has  been 
changed  to  a  sugar  or  other  soluble  bodies.  In  both  cases 
substances  insoluble  in  water  have  become  soluble  and 
diffusible. 

The  cause  of  these  changes  is  the  presence  of  typical 
bodies,  one  in  the  pig's  stomach  and  one  in  the  malt,  fer- 
ments of  the  enzym  class,  the  former  of  which  renders 
proteins  soluble,  the  latter  acting  to  produce  a  similar 
result  with  the  insoluble  carbohydrates.  This  action  is 
different  from  that  of  the  organized  ferments,  where  oxi- 
dation occurs  in  many  cases.  The  enzyms  simply  induce) 
the  proteins  and  starch  to  take  up  the  elements  of  water,i 
which  apparently  does  not  greatly  diminish  their  energy 


92  Principles  of  Human  Nutrition 

value.  How  this  is  done  cannot  be  explained  in  simple 
terms,  if  at  all.  Our  knowledge  of  the  manner  of  the  change 
rests  entirely  upon  theoretical  grounds.  The  digestion  of 
food  is  largely  accomplished  through  the  specific  effect  of 
enzym  bodies,  of  which  every  digestive  fluid  contains  one 
or  more.  Examples  of  these  are  the  pepsin  and  pancreatin 
of  the  drug  store  that  contain  enzyms  mixed  with  more  or 
less  of  impurities.  The  various  enzyms  are  often  given 
names  according  to  their  function  :  invertase,  which  inverts 
or  splits  sucrose;  glucase,  that  changes  any  carbohydrate 
into  glucose;  lactase,  that  splits  lactose  into  simpler 
sugars.  In  general,  the  ferments  acting  on  starch  are 
called  diastases.  Those  acting  on  proteins  to  produce 
hydrolysis  and  cleavage  are  designated  as  proteolytic. 

B.   THE  MOUTH 

98.  Mastication.  —  The  first  step  in  the  digestion  of 
food  is  to  reduce  it  to  a  much  finer  condition.  This  is 
done  in  the  mouth,  the  teeth  being  the  grinding  tools. 
This  comminution  is  essential  for  two  reasons:  (1)  it  puts 
the  food  in  condition  to  be  swallowed,  and  (2)  fits  it  for 
the  prompt  and  efficient  action  .of  the  several  digestive 
fluids.  It  is  necessary  for  all  food  materials  to  be  broken 
down  and  moistened  in  order  that  they  may4l>e  swallowed. 
Even  if  they  could  be  conveyed  to  the  stomach  in  a  coarse 
form,  the  process  of  rendering  their  constituents  soluble 
would  proceed  very  slowly.  Common  experience  teaches 
us  how  much  more  quickly  finely  powdered  sugar  or  salt 
will  dissolve  than  will  the  large  crystals  or  lumps.  The 
more  finely  any  solid  is  ground,  the  larger  is  the  surface 
exposed  to  the  attack  of  the  dissolving  liquid. 


The  Saliva  in  Digestion 


93 


Prompt  and  rapid  solution  of  food  is  essential,  because, 
if  it  is  too  long  delayed,  uncomfortable  and  injurious  fer- 
mentations are  likely  to  set  in,  and,  because  of  imperfect 
digestion,  the  final  nutritive  effect  of  a  meal  may  be 
diminished,  and  health  may  be  impaired.  For  these 


FIG.    1.  —  Glands  secreting   the  saliva,  —  parotid,  sublingual,   sub- 
maxillary. 

reasons,  persons  with  diseased  teeth,  or  those  who  have 
lost  teeth,  may  not  properly  prepare  their  food  for  diges- 
tion. 

99.  The  saliva.  —  During  mastication  there  is  poured 
into  the  mouth  a  liquid  called  the  saliva,  which  has  two 
important  functions :  (1)  it  moistens  the  food,  and  (2)  it 


94  Principles  of  Human  Nutrition 

causes  a  chemical  change  in  certain  of  the  constituents  of 
the  food. 

The  saliva  has  its  origin  in  several  secretory  glands 
known  as  the  salivary  glands  that  are  adjacent  to  the 
mouth  cavity,  and  from  these  this  liquid  is  poured  into  the 
mouth  through  ducts  that  open  in  the  cheek  and  under  the 
tongue.  The  chief  of  these  glands  are  located  in  the  side 
of  the  face  just  in  front  of  the  ear,  and  between  the  lower 
jaw  and  the  floor  of  the  mouth,  and  are  called  the  parotid, 
the  submaxillary,  and  the  sublingual.  Other  glands  of 
this  character  are  scattered  in  the  cheeks  and  at  the  base 
of  the  tongue.  The  anatomy  and  arrangement  of  these 
organs  are  not  essential  to  our  subject.  We  are  chiefly 
interested  in  the  liquid  which  they  secrete. 

100.  The  saliva  and  its  action.  —  The  saliva  is  a 
transparent  and  somewhat  slimy  liquid,  and  contains 
generally  not  less  than  99  parts  in  100  of  water,  and 
one  part  or  less  of  solid  matter.  It  is  alkaline  in  re- 
action, because  of  the  presence  of  compounds  of  the 
alkalies.  The  specific  chemical  effect  exerted  by  this 
liquid  on  the  food  constituents  is  shown  by  subjecting  starch 
to  its  action.  When  this  is  done,  the  starch  gradually 
disappears  as  such  and  is  replaced  by  a  solution  of  maltose, 
the  same  sugar  that  we  find  in  barley  malt.  The  agent 
which  is  active  in  causing  this  change  is  a  ferment,  ptyalin, 
which  is  always  present  in  the  saliva  of  man  and  of  some 
animals.  It  is  classed  among  the  diastatic  ferments, 
because  it  has  an  office  similar  to  that  of  a  diastase  in  the 
germination  of  seeds ;  viz.,  the  transformation  of  starch 
into  a  sugar.  This  transformation  proceeds  through 
successive  stages  from  starch  to  dextrins,  and  from  dextrins 


The  Stomach  —  Gastric  Juice  95 

to  maltose.  Cooked  starch  is  readily  susceptible  to  the 
action  of  saliva,  while  raw  starch  is  more  slowly  attacked 
by  it.  This  does  not  mean  that  raw  starch  may  not  be 
finally  digested  by  the  human  subject.  This  change  begins 
in  the  mouth,  and  probably  continues  in  the  stomach,  until 
the  food  becomes  so  acid  that  the  ferment  ceases  to  act,  for 
ptyalin  is  inactive  in  an  acid  medium. 

The  action  of  saliva  in  the  stomach  does  not  cease  sud- 
denly, however,  but  proceeds  until  the  masticated  food  is 
rendered  wholly  acid  by  mixing  with  the  gastric  juice. 
There  is  a  not  inconsiderable  absorption  of  sugar  from  the 
stomach,  notwithstanding  the  fact  that  the  stomach 
secretes  no  agent  that  acts  on  starch.  A  certain  proportion 
of  the  starch  of  foods  is  acted  on  by  the  saliva,  partly  in 
the  stomach,  but.  the  main  transformation  to  sugar  occurs 
farther  on  in  the  digestive  tract.  The  saliva  also  moistens  the 
food,  which  is  a  most  important  office,  for  it  is  a  necessary  \ 
preparation  to  the  act  of  swallowing.  It  is  estimated  that  an 
adult  secretes  not  far  from  one  quart  of  saliva  in  24  hours. 

C.   THE  STOMACH 

101.  The  gastric  juice.  —  When  the  food  leaves  the 
mouth,  it  passes  down  the  esophagus  into  the  stomach. . 
The  only  modifications  it  has  suffered  up  to  this'  point 
are  its  reduction  to  a  finer  condition  and  a  slight  action 
of  the  mouth  ferment  upon  the  starch.  After  the  food  is 
swallowed,  changes  of  another  kind  begin,  affecting  the 
protein  compounds  especially.  There  is  at  once  poured 
upon  the  food  the  gastric  juice,  a  liquid  that  is  secreted  in 
large  quantity  by  glands  located  in  the  inner  or  mucous 
membrane  of  the  stomach.  This  juice,  like  all  the  diges- 


96 


Principles  of  Human  Nutrition 


tive  fluids,  is 
mostly  water, 
the  proportion 
being  between 
98  and.  99  parts 
of  water  to  less 
than  two  parts 
of  solids.  The 
latter  consist  of 
ferments,  a  cer- 
tain amount  of 
free  or  uncom- 
biired  hydro- 
chloric acid, 
and  a  variety  of 
mineral  com- 
pounds, promi- 
nent among 
which  are  cal- 
cium and  mag- 
nesium phos- 
phates and  the 
chlorides  of  the 
alkalies,  com- 
mon salt,  being 
especially  abun- 
dant. 

FIG.  2. — Position  of  organs  of  thorax  and  abdomen  that        1A9      r 
are  related  to  digestion  and  excretion.    (MORROW.)  U^'     ^astric 

enzyms.  —  Es- 
pecial interest  pertains  to  the  ferments  of  the  gastric 
juice,  one  of  which,  in  connection  with  free  hydro- 


Digestion  in  Stomach  97 

chloric  acid,  causes  a  most  important  change  in  the 
proteins  of  the  food,  such  as  egg  albumin  and  the 
gliadin  and  glutenin  of  the  wheat  kernel  by  reducing  them 
to  soluble  forms.  We  know  quite  definitely  about  this 
action,  because  it  can  be  very  successfully  produced  in  an 
artificially  prepared  liquid.  If  the  mucous  lining  of  a 
pig's  stomach,  after  carefully  cleaning  without  washing 
with  water,  is  warmed  for  some  hours  in  a  very  dilute 
solution  of  hydrochloric  acid,  an  extract  is  obtained  which 
has  the  power  of  dissolving  lean  meat,  wheat  gluten,  and 
other  protein  substances.  The  active  agent  in  causing! 
this  solution  is  pepsin,  an  unorganized  ferment  or  enzym 
which  is  present  iii  the  gastric  fluid  of  all  animals.  It; 
changes  proteins  to  peptones,  bodies  that  are  soluble  and 
diffusible.  This  change  is  not  a  single  step,  for  the  protein 
passes  through  successive  stages  in  the  form  of  proteosesA 
before  it  reaches  the  peptone  form.  Another  ferment  \ 
present  in  the  gastric  juice  is  the  one  which  gives  to  rennet  j 
its  value  as  a  means  of  coagulating  the  casein  of  milk  in 
cheese-making,  and  is  called  rennin.  The  action  of  this 
latter  body  is  especially  prominent  in  the  stomach  of  the 
calf  when  fed  exclusively  on  milk,  and  it  is  the  calf's  active 
stomach,  the  fourth  in  the  mature  animal,  which  is  the 
source  of  commercial  rennet.  A  similar  coagulation  of 
casein  takes  place  in  the  human  stomach,  especially  no- 
ticeable in  the  milk  that  is  rejected  from  the  stomachs  of 
infants,  this  being  a  normal  result  in  digestion.  Some 
investigators  do  not  distinguish  between  rennin  and  pepsin. 
Still  another  ferment  which  food  meets  in  the  stomach 
is  lipase.(steapsin),  that  has  the  property  of  decomposing 
fats.  This  ferment,  or  similar  ones,  plays  a  prominent 


98 


Principles  of  Human  Nutrition 


part  in  intestinal  digestion,  but  there  is  no  proof  that  the 
fats  are  acted  on  in  the  stomach  to  any  appreciable  extent 
when  they  enter  the  stomach  in  meat  or  other  solid  or 
liquid  forms.  Emulsified  fats  appear  to  be  quite  exten- 
sively acted  on  in  the  stomach,  especially  in  milk,  a 
fact  important  in  the  feeding  of  infants.  Recent  in- 
vestigations, particularly  those  of  Cannon,  have  brought 
out  some  very  interesting  facts  concerning  the  way  in 
which  the  stomach  manages  the  food  during  its  re- 
tention in  that  organ.  The  following  diagrams 1  show 


FIG.  3.  —  Changes  in  the  form  of  the  stomach  during  digestion. 
a.  fundus.      6.  pylorus.       c.  middle  portion.       d.  duodenal  region. 

the  general  arrangement  of  the  parts  of  the  stomach 
and  its  changes  in  form  during  digestion.  The  food 
is  introduced  into  the  stomach  through  the  esophagus 
and  is  lodged  first  in  the  fundus  or  cardiac  end. 
From  there  it  is  moved  by  degrees  toward  the  py- 
lorus from  which  it  enters  the  small  intestine.  It 

1  Originally  appearing  in  American  Journal  of  Physiology,  1898,  Vol. 
1,  p.  370. 


Digestion  in  Stomach  99 

has  been  taught  that  this  movement  is  brought  about 
by  the  churning  of  the  stomach  throughout  its  entire 
length.  Cannon  showed  the  error  of  this  conclusion. 
From  his  observations  it  appears  that  the  fundus  end 
of  the  stomach  is  quiet  at  first.  The  waves  of  peri- 
staltic constriction  begin  at  the  duodenal  and  middle 
portions  and  move  the  food  toward  the  pylorus.  In 
this  way  the  constrictions  that  begin  near  the  pyloric 
end  gradually  extend  toward  the  cardiac  end.  The 
latter  part  of  the  stomach  is  distended  after  a  full  meal, 
but  gradually  diminishes  in  size  during  digestion.  More- 
over, the  character  of  the  gastric  juice  is  not  the  same 
from  the  different  areas  of  the  stomach,  that  from  the 
middle  portion  being  rich  in  acid,  and  that  from  the 
cardiac  and  pyloric  ends  being  neutral  or  nearly  so. 
These  facts  show  that  the  food  remains  for  some  time 
in  the  fundus  and  meets  there  a  neutral  liquid,  con- 
sequently the  alkalinity  of  the  mass  is  maintained  for 
a  time,  and  the  saliva  acts  on  the  starch  for  a  much 
longer  period  than  has  been  supposed.  It  is  believed, 
too,  that  the  length  of  time  the  food  remains  in  the 
stomach  varies  with  its  kind.  The  digesting  mass  is 
not  forced  into  the  intestine,  until  it  becomes  well  satu- 
rated with  free  acid  at  the  pylorus,  a  result  that  will  be 
reached  later  with  a  meat,  than  with  a  vegetable, 
diet;  for  it  is  plain  that  much  more  acid  will  be  re- 
quired to  combine  with  the  proteins  of  the  meat  than 
with  the  smaller  amounts  in  carbohydrate  foods  and  so 
free  acid  is  longer  in  accumulating. 

103.  Gastric  stimuli. — The  gastric  juice  is  not  constantly 
poured  into  the  stomach  to   accumulate  there,   but  is 


100  Principles  of  Human  Nutrition 

secreted  as  it  is  needed  under  the  influence  of  certain 
stimuli.  These  stimuli  may  be  classed  as  psychic  and 
\chemical.  Appetizing  odors  when  there  is  a  strong  de- 
sire to  eat,  and  the  agreeable  taste  of  food  in  the  mouth 
of  a  hungry  person  are  important  psychic  or  "  nervous  " 
influences  that  promote  gastric  digestion  through  an  ade- 
quate supply  of  the  digesting  fluid.  Other  stimuli  that  may 
be  called  chemical,  are  the  direct  or  indirect  reaction  of 
certain  substances  such  as  meat  extracts,  proteoses,  sugars, 
alcohol,  and  condiments,  upon  the  secretory  activity  of  the 
stomach.  This  stimulus  comes  later  than  the  psychic, 
but  is  more  prolonged.  The  more  recent  researches  in- 
dicate that  the  first  products  of  digestion,  reacting  on  the 
stomach  inner  membranes,  cause  the  formation  of  a  sub- 
stance, a  secretin,  which,  carried  by  the  blood  stream  to 
the  cells  of  the  stomach  glands,  excites  gastric  secretion. 
It  now  seems  possible  that  sometime  we  shall  have  a 
definite  dietetic  method  of  influencing  gastric  secretion 
rather  than  a  medicinal,  for  it  appears  that  certain  food 
compounds  may  stimulate,  and  others,  such  as  fats,  re- 
tard, stomach  activity.  The  psychic  (nervous)  factor  is 
no  less  important.  If  this  is  so,  it  is  seen  how  necessary 
it  is  that  one  shall  eat  with  pleasure  rather  than  through 
compulsion.  Satisfaction  with  one's  diet  is  a  determina- 
tive element  in  good  digestion.  Moreover,  condimental 
stimulation  is  a  poor  makeshift  for  the  effect  of  a  healthy 
liking  for  food. 

Digestion  is  aided  by  movement  of  the  ingested  food 
mass  through  contractions  of  the  walls  of  the  stomach. 
It  is  easy  to  see  how  bad  digestion  occurs  in  a  stomach 
that  is  weak  muscularly  or  that  fails  to  secrete  gastric 


Digestion  in  Intestines 


101  < 


juice  sufficient  in  quantity  or  normal  in  constitution,  and 
how  difficult  it  is  to  remedy  such  conditions. 

D.   DIGESTION  IN  THE  INTESTINES 

The  chemical  changes  which  the  food  undergoes  in  the 
large  and  small  intestines  are  exceedingly  complex  and 
concerning  which  we  have  greatly  insufficient  knowledge. 
When  the  partly  digested  food  from  the  stomach  (chyme) 


COMMON    BILE  DUCT 


ORIFICE  OF 

ACCESSORY  - 

PANCREATIC  DUCT 


ORIFICE  OF  BILE 
AND  PAWCBEATI.C  DU.CTff 


SUP. 
MESE6TTER1C  ARTERY 


FIG.  4.  —  Ducts   introducing  the   bile    and  pancreatic  juice  into  small 
intestine.     (GERRISH.) 


'•  102* :  »v :       Princvph^i)f  Human  Nutrition 

reaches  the  intestines,  it  meets  several  liquids  secreted  by 
such  special  glands  as  the  liver,  pancreas  (sweet  bread), 
and  certain  smaller  glands  that  are  distributed  in  the 
membranes  of  the  intestinal  walls.  The  liver  secretes 
the  bile,  pancreatic  juice  comes  from  the  pancreas,  and 
various  intestinal  juices  flow  from  the  small  glands  along 
the  intestinal  walls. 

104.  The  bile.  —  This  is  a  secretion  of  the  cells  of  the 
liver  and  from  the  inner  wall  of  the  gall  bladder,  that  from 
the  former  source  being  thinner,  less  ropy,  and  poorer  in 
solid  matter  than  that  secreted  by  the  gall  bladder.     After 
elaboration,  bile  is  stored  in  part,  at  least,  in  the  gall  bladder. 
Human  bile  is  a  golden  yellow  liquid,  alkaline,  and  bitter 
in  taste.     That  from  the  gall  bladder  has  been  found  to 
contain  from  82  per  cent  to   90  per  cent  of  water  or 
from  10  per  cent  to  18  per  cent  of  solid  matter.     The 
liver  bile  is  poorer  in  solids,  analyses  showing  the  pro- 
portion of  water  to  be  from  96.5  per  cent  to  97.5  per 
cent.      The  solids   of  bile  include    a    great    variety    of 
compounds,  the  chief est  of  which  are  certain  bile  salts 
and  pigments. 

Numerous  other  compounds  are  present,  such  as  fats, 
soaps,  cholesterin,  urea,  and  mineral  salts. 

105.  Bile  salts.  —  The  bile  salts  are  mainly  sodium  com- 
pounds of  glycocholic,  taurocholic,  and  related  acids  and  the 
best-known  pigments  which  occur  under  normal  conditions 
are  bilirubin,  which  is  reddish  yellow,  and  biliverdin,  which 
is  green.     Several  other  pigments  occur  in  the  concretions 
which  form  in  the  gall  bladder,  known  as  gallstones.     No 
ferment  (enzym)  has  been  found  in  the  bile,  at  least  in 
more  than  traces. 


The  Bile  —  Pancreatic  Juice  103 

106.  Secretion  of  bile.  —  The  secretion  of  the  bile  is 
irregular  in  quantity,  and,  as  is  the  case  with  gastric  juice, 
appears  to  be  induced  by  chemical  excitants  of  which  acids, 
especially  hydrochloric,  seem  to  be  especially  effective. 
Of  the  nutrients,  the  proteins  exert  the  most  influence  in 
this  respect.  The  acceleration  of  secretion  occurs  at  a 
greatly  varying  time  after  food  ingestion,  the  maximum 
flow  being  determined  by  the  kind  of  food. 

The  bile  compounds  are  in  evidence  in  certain  patho- 
logical conditions.  When  for  any  reason  the  discharge 
of  bile  into  the  intestine  is  retarded  and  the  organism 
attempts  to  eliminate  it  through  the  kidneys,  the  tissues 
become  charged  with  its  compounds  and  take  on  a  yellow- 
ish coloration,  and  the  subject  is  said  to  have  jaundice,  - 
a  condition  sometimes  attended  with  serious  results.  Con- 
cretions are  formed  in  the  gall  bladder  that  in  man  are 
characterized  by  the  presence  of  cholesterin,  a  bile  com- 
pound. 

107.-  The  pancreatic  juice. — This  secretion  has  the  most 
comprehensive  action  on  the  food  nutrients  of  any  one  of 
the  intestinal  liquids.  It  originates  in  the  pancreas  (sweet 
bread).  Its  flow  is  intermittent,  being  induced  by  the  re- 
action especially  of  the  acids  in  the  partially  digested  foods 
from  the  stomach.  The  amount  secreted  and  its  compo- 
sition appear  to  change  with  the  kind  of  food.  It  contains 
about  87.5  per  cent  of  water  and  12.5  per  cent  of  solid 
matter.  This  secretion  acts  upon  all  classes  of  nutrients, 
as  it  contains  a  variety  of  ferments  greatly  unlike  in  func- 
tion. 

108.  Protein-splitting  enzyms. — Among  these  are  at 
least  two,  and  possibly  several,  which  act  on  proteins, 


104  Principles  of  Human  Nutrition 

including  trypsin  (possibly  not  a  single  body),  as  the 
main  one,  and  one  that,  like  erepsin  (see  p..  105),  splits 
peptones  into  simpler  compounds  and  seems  to  supple- 
ment the  action  of  trypsin.  Trypsin  acts  in  neutral  or 
in  alkaline  solutions,  a  free  mineral  acid  like  hydrochloric 
completely  stopping  its  operation.  Organic  acids,  like 
lactic,  do  not  seem  to  have  this  effect.  In  conjunction 
with  other  enzyms,  it  splits  food  proteins  into  simpler 
compounds,  viz.,  monamino  and  diamino  acids,  tryptophane 
and  other  bodies,  all  of  which  may  be  regarded  as  the  build- 
ing stones  of  the  original  proteins.  As  we  have  seen, 
these  simpler  bodies  are  not  the  same  in  kind  or  propor- 
tions for  all  proteins,  (^y^ 

109.  Steapsin.  —  The    pancreatic  secretion  acts  vig- 
orously on  fats,  not  only  splitting  them  into  fatty  acids 
and  glycerin,  but,  in  conjunction  with  the  bile,  also  effects 
their  emulsification,  this  latter  result  being  aided,  doubt- 
less, by  the  soaps  which  are  formed  from  a  union  of  the 
fatty  acids  and  the  alkaline  bases  (mostly  sodium)  in  the 
bile.     This  is  a  true  saponification.     The  cleavage  of  the 
fats  is  due  to  an  enzym  to  which  the  name  of  steapsin  is 
given,  also  called  lipase.' 

110.  Amylopsin.  —  We  have  seen  that  starch  is  acted 
upon  to  a  small  extent  by  the  saliva,  and  that  this  action 
is  not  prolonged  in  the  stomach  beyond  the  time  when  the 
stomach  contents  become  fully  acidified.     Starch  digestion 

/is  therefore  carried  on  mainly  in  the  intestines,  chiefly, 
if  not  wholly,  by  a  diastatic  ferment  in  the  pancreatic 
juice  which  has  the  power  of  hydrolyzing  the  starch  mostly 
into  maltose.  This  pancreatic  diastase,  called  amylopsin 
by  some  authors,  is  not  found  in  the  digestive  tract  of 


Intestinal  Juices — Bacteria  105 

infants  until  more  than  one  month  after  birth.     The  pres- 
ence of  bile  is  very  favorable  to  its  action. 

111.  Intestinal  juices.  —  Mention  has  been  made    of 
juices  that  are  secreted  by  small  glands  distributed  in  the 
walls  of  the  intestines.     These  appear  to  be  quite  impor- 
tant factors  in  digestion,  as  they  supplement  the  action  of 
the  ferments  of  the  pancreatic  juice.     It  appears  to  be 
shown  that  an  enzym  erepsin  is  found    in    these  juices, 
that  is  unable  to  act  upon  any  of  the  native  proteins  ex- 
cept casein,  but  has  the  power  of  decomposing  proteoses 
and  peptones  into  simpler  compounds,  particularly  the 
amino  acids.     These  secretions  seem  to  contain,  also,  a 
ferment  that  converts  maltose  into  dextrose,  and  in  infants 
and  young  animals  they  also  contain  a  lactose-  (milk  sugar) 
splitting  enzym.     It  is  held  that  trypsin  does  not  exist 
as  such  in  the  pancreatic  juice  when  poured  into  the 
small  intestine,  but  that  this  enzym  is  formed  from  a 
mother  substance   (trypsinogen)   in  the  pancreatic  juice 
after  it  comes  in  contact  with  the  intestinal  juice,  this 
result  being  accomplished  through  the  action  of  a  body, 
probably  secreted  from  the  intestinal  walls  and  called  by 
Pawlow  enterokinase. 

112.  Intestinal    bacteria.  —  So   far,  in   presenting   the 
relation  of  ferments  to  digestion,  only  the  unorganized 
ferments  or  enzyms  have  been  considered.     While  these 
are  chiefly  concerned  in  normal  digestion,  organized  fer- 
ments are  present  throughout  the  entire  intestinal  canal 
and  play  a  part  in  food  changes.     They  are  most  abundant 
and  active  in  the  lower  part  of  the  small  intestine  and  the 
upper  part  of  the  large.     They  act  upon  the  proteins,  caus- 
ing putrefaction,  dissolve  cellulose,  and  cause  a  decom- 


106  Principles  of  Human  Nutrition 

position  of  the  carbohydrates.  The  products  of  these 
fermentations  may  be  in  part  the  same  as  those  produced 
in  pancreatic  digestion,  but  these  include  also  indol  and 
skatol,  which  have  the  characteristic  fecal  odor,  volatile 
fatty  acids,  and  gases,  some  of  which  are  carbon  dioxid, 
hydrogen,  marsh  gas,  and  hydrogen  sulfide. 

Under  certain  conditions  fermentations  of  this  character, 
which  up  to  a  certain  extent  are  normal  and  may  be  bene- 
ficial, proceed  so  far  as  to  be  deleterious  to  health.  Any- 
thing which  retards  digestion,  such  as  imperfect  mastica- 
tion, excessive  eating,  abnormal  amounts  of  meat  in  the 
diet,  and  failure  of  the  organs  secreting  the  digestive  fluids 
to  supply  these  fluids  in  sufficient  abundance,  gives  these 
bacteria  a  better  opportunity  to  act  on  the  food  residues,  and 
increases  their  effect.  Some  foods,  especially  vegetables 
of  the  leguminous  class,  appear  to  be  provocative  of  ex- 
cessive intestinal  fermentations.  Flatulence,  and  even 
toxic  poisoning  may  be  the  result  of  great  bacterial  ac- 
tivity in  the  digestive  tract.  It  is  hardly  possible  to  check 
this  by  administering  septics,  but  purging  is  of  value  in 
removing  the  fermentative  material.  At  one  time  it  was 
held  that  the  bile  has  a  specific  antiseptic  effect,  but  later 
researches  throw  doubt  on  this  conclusion.  Probably 
the  bad  results  of  a  restricted  flow  of  bile  are  indirect,  the 
less  perfect  digestion  giving  the  bacteria  a  greater  oppor- 
tunity. Free  hydrochloric  acid  restrains  bacterial  fermen- 
tation and  has  this  effect  in  the  stomach,  but  this  influence 
can  hardly  extend  to  the  intestines,  for  the  free  acid  is 
neutralized  before  it  reaches  that  point.  Particular  foods, 
especially  milk  and  kephir,  have  been  shown  to  have  a 
preventive  action  on  putrefaction. 


Digestion  as  a  Whole  107 

113.  Digestion  of  food  as  a  whole.  —  From  what  has 
preceded  we  learn 'that  several  liquids  and  certain  organ- 
isms participate  in  producing  the  complex  changes  that 
food  undergoes  during  digestion.  Some  of  these  liquids 
have  certain  common  functions,  as  for  instance,  proteins 
are  dissolved  both  in  the  stomach  and  by  the  pancreatic 
juice.  Moreover,  the  various  digesting  fluids  appear  to 
act  cooperatively.  This  is  made  plain  by  following  the 
course  of  the  food  changes.  After  the  food  has  remained 
in  the  stomach  for  a  short  period  of  time,  it  is  gradually 
discharged  into  the  small  intestine,  the  rate  of  discharge 
varying  with  the  kind  of  food,  that  is,  with  the  promptness 
and  rapidity  of  digestion,  which  differs  with  different 
foods.  The  progress  made  up  to  this  point  in  food  trans- 
ference, so  far  as  we  have  definite  knowledge,  is  chiefly 
the  cleavage  of  the  proteins  into  various  stages  of 
hydrolysis,  the  resulting  bodies  being  proteoses  and  pep- 
tones. All  proteins  appear  to  be  acted  on  in  the  stomach, 
but  to  different  degrees  and  probably  at  different  rates.  It 
seems  probable  that  the  simple  proteins  are  as  fully  dis- 
solved as  any,  while  some  of  the  conjugated  and  derived 
proteins,  such  as  the  nucleo-proteins  and  those  that  are 
coagulated  by  heat,  are  at  least  more  slowly,  and  in  some 
cases  less  perfectly  broken  up.  Starch,  already  some- 
what dissolved  by  the  saliva,  is  not  further  acted  upon  by 
the  stomach  enzyms,  neither  are  the  solid  and  liquid  fats 
affected  to  any  discoverable  extent.  Simple  sugars  are 
not  acted  upon  by  the  gastric  juice,  but  it  seems 
probable  that  the  di-sugars  may  be  split  into  simple 
ones  by  the  hydrochloric  acid.  It  appears  then,  that 
in  the  intestines  protein  digestion  must  be  completed, 


108  Principles  of  Human  Nutrition 

the  larger  part  of  the  starch  transformed  to  sugar  and 
the  digestion  of  the  fats  wholly  accomplished  or  mainly 
so.  As  a  matter  of  fact,  the  partial  solution  in  the 
stomach  of  the  proteins  and  the  swelling  of  the  undissolved 
part  to  a  gelatinous  mass  may  be  considered  as  a  prepara- 
tion of  the  food  for  intestinal  digestion,  for  through  these 
changes  the  proteins  present  a  larger  surface  to  the  attack 
of  trypsin  and  other  intestinal  enzyms  and  digestion 
proceeds  more  promptly  than  would  be  the  case  with  the 
freshly  ingested  food.  Moreover,  the  compounds  in  the 
chyme,  especially  the  acid,  react  on  the  liver  and  pan- 
creas, and  cause  an  abundant  flow  of  digestive  fluids  from 
these  glands. 

As  soon  as  the  chyme  mixes  with  the  bile  and  pancreatic 
juice,  the  mass  is  changed  from  an  acid  to  an  alkaline  con- 
dition. This  seems  to  be  essential  to  the  effective  operation 
of  the  pancreatic  ferments.  While  the  pancreatic  juice 
wilFcarry  on  digestion  by  itself,  this  is  not  satisfactory  in 
the  absence  of  bile,  for  when  the  latter  is  not  permitted 
to  enter  the  small  intestine,  the  digestion  of  fats  is  very 
imperfect.  It  seems  essential  that  these  two  liquids  act 
together.  The  bile  aids  in  rendering  the  digesting  mass 
alkaline,  contributes  to  the  formation  and  solution  of  the 
fatty  acids  and  soaps,  and  in  these  ways  and  others  not 
altogether  explainable  promotes  the  activity  of  the  pan- 
creas enzyms.  The  juices  that  flow  from  the  small  glands 
in  the  intestinal  walls  appear  to  essentially  supplement  the 
work  of  the  bile  and  pancreatic  juice.  In  the  first  place, 
they  probably  contain  a  substance  that  makes  active  the 
mother  substance  of  trypsin,  in  the  second  place,  they  aid 
in  splitting  the  peptones  into  simpler  bodies,  and  lastly, 


Absorption  of  Food  109 

they  convert  the  sugars  into  the  final  form  (dextrose)  in 
which  they  are  absorbed  into  the  blood  circulation.  If 
we  consider  the  digestion  of  the  food  compounds  by 
classes,  the  following  is  a  summary  of  the  ways  in 
which  they  are  acted  upon :  pepsin,  tiypsin,  and  Jterepsin 
secreted  by  the  stomach,  pancreas,  and  intestinal  glands 
act  on  the  proems;  ptyalin  in  the  saliva,  amylopsin 
from  the  pancreas,  and  lactase,  maltase,  and  sucrase  in 
intestinal  secretions  act  on  the  carbohydrates,  and  the  fats 
are  acted  on  mainly  by  the  lipase  of  the  pancreatic  juice. 
The  bacteria  are  not  surely  known  to  have  necessary 
specific  functions,  unless  it  be  their  solvent  action  on  the 
cellulose.  The  various  enzym  activities  finally  prepare 
the  food  for  absorption  into  the  blood  circulation,  not 
merely  by  solution,  but  by  such  rearrangement  of  the 
ingested  food  compounds  as  to  fit  them  for  constructive 
purposes  in  the  animal  body  or  for  supplying  the  energy  that 
is  required  for  internal  and  external  work. 

E.  ABSORPTION  OF  THE  FOOD 

From  the  time  the  food  enters  the  stomach,  during  nearly 
its  entire  course^lttfg  the  alimentary  canal,  there  is  a  con- 
stant production  of  solubl^  compounds,  which  progressively 
disappear  into  other  channels,  so  that  when  the  anus  is 
reached  only  a  small  portion  of  the  original  dry  matter  is 
found  in  the  residue.  In  some  way,  not  wholly  explainable 
in  all  its  details,  the  digested  food  has  been  absorbed  and 
received  into  vessels  through  which  it  is  distributed  to  the 
various  parts  of  the  body. 

114.  Function  of  lacteals  and  blood  vessels  in  absorp- 
tion. —  A  merely  casual  observation  shows  us  that  the 


110 


Principles  of  Human  Nutrition 


inner  surface  of  the  walls  of  the  digestive  organs  are  cov- 
ered by  numerous  projections.  The  anatomist,  by  a  care- 
ful study  of  these,  has  learned  that  imbedded  in  their 
tissue,  especially  in  the  intestines,  are  the  minute  branches 


MUCOU9 
COAT 


MOSCULARfS 
MUCOS/B 


LAYER  OF  CIRCULAR  FIBRES 
LAYER  OF  LONGITUDINAL  FIBRES 


FIG.  5.  —  Cross  section   mucous   membrane  of  small  intestine,  showing 
capillaries  and  lacteals.      (GERRISH.) 

of  two  systems  of  vessels.  One  set  is  the  lacteals,  belong- 
ing to  the  so-called  lymphatic  system,  and  the  other  set  is 
the  capillaries  of  the  blood  system.  The  lymphatic  ves- 
sels or  tubes  all  lead  to  a  main  tube  or  reservoir,  the 
thoracic  duQt,  which  extends  along  the  spinal  column  and 


Absorption  of  Food 


111 


finally  enters  one  of  the  main  blood-vessels.  Any  material, 
therefore,  taken  up  by  the  lacteals  ultimately  reaches  the 
blood.  The  capillaries  all  converge  to  a  larger  blood 
vessel,  known  as  the  portal  vein,  which  enters  the  liver, 
carrying  with  it  whatever  material 
the  capillaries  have  absorbed^ 

The  manner  in  which  the  soluble 
food  is  absorbed  has  been  explained  in 
part  on  common  physical  grounds. 
When  two  solutions  of  different 
densities,  containing  diffusible  com- 
pounds, are  separated  by  a  perme- 
able membrane,  diffusion  through 
this  membrane  from  the  denser  to 
the  lighter  liquid  will  always  occur. 
Such  a  condition  as  'this  prevails  in 
the  intestines,  we  may  believe.  The 
intestinal  solution,  the  denser  one,  is 
separated  from  a  less  concentrated 
liquid,  the  blood,  which  is  constantly 
flowing  on  the  other  side  of  a  thin 
dividing  membrane.  Under  these 
conditions  there  occurs  the  passage 
into  the  blood  of  certain  parts  of  the 
digested  food.  It  is  held  that  in  this 
way  water,  soluble  mineral  salts,  and  sugar  pass  directly 
into  the  blood-vessels.  The  peptones  are  also  taken  up 
by  the  capillaries,  and  the  fats  enter  the  blood  through 
the  lacteals. 

115.    Changes  in  the  walls  of  the  intestinal  tract.  —  In 
the  absorption  of    peptones  and  fats,  at   least,  we  en- 


FIG.  6.  —  Intestinal 
villus,  showing :  a, 
epithelium;  b,  capil- 
laries; c,  lacteal  ves- 
sel. 


112  Principles  of  Human  Nutrition 

counter  forces  other  than  the  osmotic  transference  of  sub- 
stances in  solution,  the  operation  of  which  is  still  more  or 
less  unexplained. 

As  we  have  learned,  the  ingested  proteins  are  changed 
in  the  stomach  and  intestines  to  peptones,  and  in  part,  per- 
haps mainly,  to  simpler  compounds  resulting  from  the  cleav- 
age of  peptones.  The  fats  are  split  partly,  or  entirely,  into 
fatty  acids  and  glycerin,  with  the  subsequent  formation 
of  soaps  by  the  union  of  the  free  acids  with  the  alkaline 
bases  of  the  bile.  There  is  good  evidence  that  in  the  pas- 
sage of  these  new  compounds  through  the  walls  of  the 
intestine  changes  occur  of  a  synthetical  character,  with  a 
partial  or  total  reconstruction  of  the  proteins  and  fats  into 
forms  similar  to  those  in  the  ingested  food.  The  rebuild- 
ing of  fats  and  their  transference  into  the  lacteals  is  re- 
garded as  being  accomplished  through  the  activity  of 
cells  lying  in  the  mucous  lining  of  the  intestine.  It 
seems,  then,  that  the  vital  forces  residing  in  the  living 
cells  play  a  part  in  transferring  the  nutrients  into 
the  blood  circulation,  and  that  this  absorption  can  no 
longer  be  explained  wholly  on  the  basis  of  osmotic  pressure. 

116.  Place  of  maximum  absorption.  —  Absorption  of 
digested  food  undoubtedly  takes  place  in  the  stomach, 
but  the  main  transference  of  the  products  of  digestion  into 
the  blood  is  from  the  intestines,  particularly  the  small 
intestine.  Much  of  the  water  that  passes  into  the  large 
intestine  is  absorbed  there,  together  with  the  products 
of  digestion  not  already  absorbed  and  those  products  that 
result  from  bacterial  action.  It  is  a  question  of  impor- 
tance whether  there  is  an  absorption  of  proteins  when 
the  lower  intestine  is  flooded  with  an  enema  containing 


Feces 


proteins  such  as  the  white 
of  an  egg.  The  evidence 
is  that  under  these  cir- 
cumstances protein  ab- 
sorption occurs  and  fur- 
nishes a  very  fortunate 
means  of  nourishing  a 
patient  when  the  ordi- 
nary method  of  digestion 
is  not  possible. 

F.   FECES 

The  soluble  and  in- 
soluble portions  of  the 
intestinal  contents  be- 
come separated  gradu- 
ally, and  the  undissolved 
part  arrives  finally  at  the 
last  stage  of  its  journey 
along  the  alimentary 
canal,  and  is  expelled  as 
the  solid  excrement,  or 
feces.  This  is  made  up 
of  the  undigested  food 
and  other  matter,  such  as 
residues  from  the  bile 
and  other  digestive  juices, 
mucus,  and  more  or  less 
of  the  epithelial  cells 
which  have  become  de- 
tached from  the  walls  of 


FIG.  7.  —  Lacteals  during  digestion. 
(COLLINS.) 


114  Principles  of  Human  Nutrition 

the  stomach  and  intestines.  Dead  and  living  bacteria 
appear  to  constitute  a  considerable  portion  of  the  fecal 
matter.  These  organisms  are  not  taken  in  with  the  food 
to  any  great*  extent,  but  are  the  result  of  their  continuous 
growth  in  the  lower  intestines.  Small  quantities  of  fer- 
mentation products  are  present,  which  give  to  the  feces 
its  offensive  odor.  The  incidental  or  waste  products  may 
properly  be  considered  as  belonging  to  the  wear  and  tear 
of  digestion.  > 

The  ordinary  conception  of  the  fecal  residue  is  that  it 
is  only  the  part  of  the  food  that  has  resisted  the  action  of 
the  digestive  fluids,  but  in  fact  it  is  much  more  than  that. 
Not  only  does  it  include  the  various  waste  products  pre- 
viously referred  to,  but  also  compounds  that  have  been 
absorbed  into  the  blood  circulation  and  returned  to  the 
alimentary  canal  for  excretion.  It  has  been  shown  that 
when  a  phosphorus  compound  was  injected  subcutane- 
ous^ into  a  sheep,  the  phosphorus  was  excreted  in  the 
feces  in  another  combination.  It  is  also  proven  that 
mineral  compounds  absorbed  from  the  intestinal  tract  may 
afterwards  appear  in  the  feces. 

G.  THE  RELATION  OF  THE  DIFFERENT  FOOD  COMPOUNDS 
TO  THE  DIGESTIVE  PROCESSES 

Numerous  digestion  experiments  with  a  large  variety 
of  foods  have  abundantly  established  the  fact  that  these 
materials  differ  greatly  in  their  solubility  in  the  digestive 
juices.  This  is  an  important  matter,  and  one  which  should 
be  well  understood,  for  we  must  consider  both  the  weight 
of  the  food  eaten  and  its  availability  in  determining  its 


Digestion  of  Proteins  115 

nutritive  value.  Variations  in  digestibility  are  caused 
primarily  by  variations  in  composition,  therefore,  we  must 
deal  fundamentally  with  the  susceptibility  of  the  various 
single  constituents  of  foods  to  the  dissolving  action  of 
the  several  digestive  ferments. 

In  this  connection,  we  need  to  pay  little  attention  to  the 
mineral  compounds.  They  do  not  undergo  fermentative 
changes  in  the  way  that  the  carbon  compounds  do,  but  pass 
into  simple  solution  either  in  the  water  accompanying 
the  food,  or  in  the  juices  with  which  they  come  in 
contact. 

117.  Digestibility  of  the  proteins.  —  As  has  been  noted, 
protein  is  a  mixture  of  nitrogenous  compounds.  The 
gluten  of  wheat  contains  at  least  five  of  these  bodies,  and 
other  seeds  as  many.  What  is  the  relative  susceptibility 
of  these  single  proteins  to  ferment  action  either  as  to 
rapidity  or  completeness  of  change  does  not  appear  to  be 
known.  Some  proteins  are  practically  all  digested  by 
artificial  methods,  and  probably  are  in  natural  digestion. 
It  is  a  fact,  however,  that  protein  is  much  more  completely 
dissolved  from  some  foods  than  from  others.  That  of 
milk  and  meat  is  practically  all  digestible,  that  of  some 
grains  very  largely  so,  while  with  vegetables  quite  a  large 
proportion  escapes  solution.  Whether  this  is  due  to  a 
differing  degree  of  solubility  on  the  part  of  the  character- 
istic protein  compounds  of  the  various  foods  is  not  quite 
determined.  The  fact  that  highly  fibrous  materials  show 
the  lowest  proportion  of  digestible  protein  suggests  as  an 
explanation  that  the  nitrogen  compounds  of  plant  tissue 
are  so  protected  by  the  fiber  present  that  they  escape 
the  full  action  of  the  digestive  juices.  It  is  certain,  how- 


116  Principles  of  Human  Nutrition 

ever,  that  the  protein  in  plant  tissue  is  less  fully  digested 
than  that  from  milk,  meat,  and  eggs. 

118.  Digestibility  of  the  Carbohydrates.  —  In  the  case 
of  the  carbohydrates,  our  knowledge  of  the  relative  suscep- 
tibility of  the  individual  compounds  to  enzym  action  is 
more  definite.  First  of  all,  the  necessary  modification  of 
the  sugars,  which  are  already  soluble,  is  slight,  and  they  are 
wholly  digested.  In  the  second  place,  we  have  learned  in 
two  ways  that  the  starches  are  wholly  transformed  to  diffus- 
ible compounds,  first  by  submitting  them  in  an  artificial  way 
to  the  action  of  various  diastatic  ferments,  and,  second, 
by  discovering  a  complete  absence  of  starch  or  its  prod- 
ucts in  normal  human  feces.  We  can  say,  therefore, 
that  under  normal  -conditions  the  unprotected  starches, 
like  the  sugars,  are  completely  digestible. 

Digestibility  must  be  considered,  however,  from  the 
standpoints  both  of  rapidity  and  of  completeness.  As  to 
the  former  factor,  starches  from  unlike  sources  exhibit 
some  remarkable  differences.  Investigations  by  Stone, 
who  submitted  a  number  of  these  bodies  to  the  action  of 
several  diastatic  ferments,  show  that  "  this  variation 
reaches  such  a  degree  that  under  precisely  the  same  condi- 
tions certain  of  the  starches  require  eighty  times  as  long 
as  others  for  complete  solution."  The  potato  starches 
appear  to  be  acted  upon  much  more  rapidly  than  those 
from  the  cereal  grains. 

Other  carbohydrates,  cellulose  and  hemicelluloses,  such 
as  pentosans,  galactan  and  mannan  and  related  bodies, 
show  great  variations  in  digestibility  according  to  their 
source,  these  variations  ranging  in  observations  by  Swartz 
from  0  to  100  per  cent.  The  extent  to  which  these  sub- 


Digestion  of  Fats  117 

stances  disappear  from  the  alimentary  canal  appears  to 
be  dependent  on  their  solubility  and  their  susceptibility 
to  attack  by  bacteria. 

119.  Digestibility  of  the  fats.  —  The  extent  of  the  diges- 
tion and  absorption  of  the  fats  or  oils  is  also  not  definitely 
known.  If  we  were  to  accept  the  figures  given  for  ether- 
extract  in  tables  of  digestion  coefficients  as  applying  to 
the  real  fats,  we  would  believe  that  their  digestibility 
varies  from  less  than  one-third  to  the  total  amount.  It  is 
unfortunately  true  that  these  coefficients  mean  but  very 
little.  The  ether-extract  from  some  foods  is  only  partially 
fat  or  oil,  as  we  have  seen,  and  the  inaccuracy  of  a  diges- 
tion trial  is  still  further  aggravated  by  the  presence  in  the 
feces  of  bile  residues  and  other  bodies  which  are  soluble  in 
ether,  so  that  the  difference  between  the  ether-extract  in 
the  ingested  food  and  that  in  the  feces  does  not  give 
accurate  information  as  to  what  has  happened  to  the  actual 
fats.  It  seems  very  probable  that  pure  vegetable  fats  and 
oils  and  all  mixed  animal  fats  are  quite  completely  ab- 
sorbed. 

The  foregoing  statements  make  it  plain  that  when  the 
general  composition  of  a  food  is  known,  it  is  possible  to 
predict  with  a  good  degree  of  certainty  whether  its  rate 
of  digestibility  is  high  or  low.  The  larger  the  proportion 
of  starch,  sugar,  milk,  meat  and  eggs  and  the  smaller  the 
percentage  of  gums  and  fiber,  the  more  complete  will  be 
the  solution. 

H.    FACTORS  WHICH  MAY  INFLUENCE  DIGESTION 

Digestion  has  an  important  relation  to  the  nutritive 
efficiency  of  food,  and  to  the  physical  welfare  of  the  indi- 


118  Principles  of  Human  Nutrition 

vidual.  On  the  one  hand,  only  that  portion  of  the  food 
that  is  digested  and  absorbed  can  serve  the  purposes  of 
growth  and  the  maintenance  of  the  vital  functions,  and 
on  the  other  hand,  bad  digestion  causes  discomfort  and 
disease. 

120.  Meaning  of  "  digestibility."  —  In  discussing  the 
factors  that  may  influence  the  digestion  of  food,  it  is 
essential  to  understand  clearly  what  is  involved  in  the 
term  digestion  as  it  is  used  in  science  and  in  common 
speech.     The  term  is  made  to  include  three  elements, 
completeness    of   solution    and    absorption   of   the    food 
nutrients,  rate  of  digestion,  and  comfort  of  digestion.     In 
science,  the  figures  that  are  given  for  the  digestibility  of 
various  foods  refer  to  the  completeness  or  extent  to  which 
the  food  is  dissolved  and  transferred  to  the  circulation. 
But  different  foods  from  which  come  the  same  proportion 
of  undigested  dry  matter  may  differ  materially  in  the  rate 
at  which  they  undergo  digestive  changes,   and  in  this 
sense  their  digestibility  is  unlike.     Again,  when  for  any 
cause  digestion  causes  discomfort,  the  sufferer  declares  that 
the  particular  food  eaten  is  not  digestible.      As  a  matter 
of  fact,  the  ultimate  completeness  of  solution  in  the  diges- 
tive fluids  may  not  be  influenced  either  by  the  rate  or  the 
discomfort  attending  the  process.     Among  the  numerous 
factors   that   may   modify   digestion,    the   following   are 
among  the  most  important :  — 

121.  Kind  of  food.  —  The  kind  of  food,  other  things 
being  equal,  determines  the  completeness  and  also,  w,e 
may  believe,   the   rate   of  digestion.     Investigation   has 
shown,  as  already  noted,  that  vegetable  foods  are  less  fully 
digested  than  those  of  animal  origin,  a  fact  due  probably, 


Factors  Influencing  Digestion 


119 


to  the  in  closure  of  the  protein  and  other  nutrients  in  the 
fibrous  tissue  of  much  vegetable  substance.  It  is  entirely 
rational  to  claim,  too,  that  this  association  of  the  nutrients 
with  a  cellulose  framework  retards  digestion  by  protecting 
the  protein  and  other  compounds  from  attack.  If  no 
allowance  is  made  for  the  metabolic  products  in  the  feces, 
the  digestibility  of  the  various  classes  of  foods  is  calculated 
to  be  as  follows  :  — 

TABLE    XIX 


PROTEINS 

CARBO- 
HYDRATES 

FATS 

Animal  foods  .... 
Cereals  ...... 

Per  Cent 
98 
85 

Per  Cent 
100 

98 

Per  Cent 
97 

90 

Vegetables  and  fruits  .  . 

8Q 

95 

90 

The  individual  nutrients  differ  in  their  susceptibility 
to  attack  by  the  digestive  fluids.  We  have  seen  that 
potato  starch  is  hydrolyzed  more  rapidly  than  that  from 
the  cereal  grains.  In  the  case  of  the  fats  the  higher  their 
melting  point  the  more  slowly  they  are  likely  to  be  decom- 
posed and  emulsified.  It  is  probable  that  tallow  requires  a 
longer  time  for  complete  digestion  than  does  butter  or  the 
salad  oils,  and  may  be  less  completely  absorbed.  This 
point  may  well  be  raised  touching  the  digestibility  of 
imitation  butter  that  is  made,  in  part  at  least,  from  the 
body  fats  of  bo  vines  and  swine. 

This  influence  of  the  melting  point  is  quite  clearly 
indicated  by  the  following  figures  :  — l 

1  "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  I,  p.  56. 


120 


Principles  of  Human  Nutrition 


TABLE    XX 


KIND  OF  FAT 

MELTING  POINT 

PER  CENT  Loss  IN 
THE  FECES 

C° 
60 

91  to  86 

Stearin  and  almond  oil     ... 

55 
53 

10.6 
31.0 

50-51 

9.2 

Mutton  fatty  acids      .... 

56 
49 

13  to  20 
7.4 

Lard                     

43 

2.6 

Pork  fat     

34 

2.8 

25 

2.5 

Olive  oil          

fluid 

2.3 

122.  Influence  of  food  on  secretions.  —  The  more 
recent  investigations  reveal  the  fact  that  the  kind  of  food 
has  an  influence  not  only  on  the  abundance,  but  on  the 
kind  of  digestive  secretions,  which  is  important,  because 
an  abundant  supply  of  digestive  juices  is  necessary  to 
good  digestion.  The  conclusion  is,  or  better  perhaps  the 
theory,  that  certain  chemical  excitants  are  conveyed  to  the 
secreting  glands  through  the  blood  circulation,  and  excite 
the  flow  of  the  several  digestive  fluids,  and  that  the  forma- 
tion of  these  excitants  is  caused  by  the  reaction  of  food 
compounds  on  the  inner  membranes  of  the  stomach  and 
intestines,  this  reaction  being  more  pronounced  with  some 
food  materials  than  with  others.  Broths,  meat  extracts, 
milk,  dextrin,  maltose,  and  dextrose  exert  a  pronounced 
influence  in  this  way  in  the  stomach,  which  makes  rational 


Influence  of  Food  on  Secretions  121 

the  taking  of  soups  or  bouillon  as  the  first  dinner  course, 
or  the  eating  of  toasted  bread  and  zwieback  by  persons 
with  weak  digestion.  On  the  other  hand,  fats  tend  to 
inhibit  gastric  secretion,  so  that  an  excessive  proportion 
of  fat  in  the  meat  might  weaken  digestion  in  the 
stomach. 

Food  may  exert  an  indirect  influence  on  the  pancreatic 
secretion.  The  acid  in  the  chyme  stimulates  the  flow  of 
the  pancreatic  juice.  Any  diet,  therefore,  that  has  the  effect 
of  diminishing  or  of  neutralizing  the  stomach  acid  which 
otherwise  would  reach  the  small  intestine  is  unfavorable 
to  pancreatic  digestion.  Mendel  1  states  that  "  the 
activity  of  the  enzyms  of  the  pancreatic  juice  seems  to  be 
correlated  in  a  marvelous  way  with  the  corresponding 
elements  of  the  diet.  A  regimen  rich  in  fat  calls  forth  a 
secretion  containing  a  relative  abundance  of  the  lipolytic 
(fat-splitting)  enzyme  ;  with  a  meat  diet,  the  proteolytic 
enzymes  preponderate,  and  so  forth.  Furthermore,  this 
regulative  action  can  apparently  be  modified  by  the  con- 
ditions of  the  diet.  One  is  almost  inclined  to  speak  of  a 
physiologic  education  of  the  digestive  glands,  and  to  con- 
ceive of  them  as  being  trained  for  fat,  or  proteid,  or  car- 
bohydrate digestion  powers  by  the  presence  of  the  corre- 
sponding compounds  in  the  alimentary  canal.  Indeed, 
this  conception  has  already  been  raised  above  the  realm 
of  mere  fancy."  Such  facts  as  these  are  significant,  and 
we  may  reasonably  hope  that  some  time  in  the  future  bad 
digestion  and  the  habit  of  constipation  may  be  relieved 
through  the  diet,  rather  than  through  medicines. 


Aspects  of  the  Newer  Physiology  of    the  Gastrointestinal 
Canal,"  p.  6. 


122  Principles  of  Human  Nutrition 

123.  Mechanical  condition  of  ingested  food.  —  It  is 
generally  held  that  thorough  mastication  of  food  promotes 
good  digestion.  This  is  rational;  although  involving 
chemical  changes,  digestion  is  broadly  considered  a  means 
of  rendering  the  nutrients  soluble,  that  is,  transferable 
through  the  walls  of  the  alimentary  canal.  The  doctrine 
has  been  taught,  in  one  notable  instance  at  least,  that 
excessive  mastication  greatly  increases  the  efficiency  of  the 
food.  If  this  is  true,  it  must  be  because  of  increased 
thoroughness  of  digestion.  Observation  does  not  show 
this  result.  It  is  concluded  from  experimental  evidence 
"  that  any  dietetic  practice,  therefore,  such  as  excessive 
mastication,  which  may  be  claimed  to  result  in  greater 
economy  in  the  utilization  of  food  so  far  as  it  relates  to 
thoroughness  of  digestion,  must  improve  upon  a  condition 
in  which  there  is  already  almost  complete  utilization." 
While  in  a  normal  subject,  careful  mastication  may  not 
increase  the  proportion  of  nutrients  that  will  ultimately 
be  digested  and  absorbed,  fineness  of  division  of  the  food 
particles  makes  for  promptness,  and  therefore  comfort, 
of  digestion,  because  the  larger  the  food  surface  which  the 
digestive  fluids  may  attack,  the  more  rapidly  will  solution 
be  effected,  which  is  highly  desirable.  Of  course  bolting 
the  food  in  coarse  pieces  may  result  not  only  in  incom- 
plete, but  uncomfortable,  digestion.  In  comparing  the 
digestibility  of  breads  from  different  kinds  of  flour,  that 
from  coarse  flour,  that  is,  whole  wheat  flour,  is  found  to  be 
less  completely  digested  than  bread  from  fine  flour,  but 
this  is  due,  not  so  much  to  the  degree  of  fineness  as  to  the 
presence  in  the  coarse  flour  of  more  cellulose  (crude  fiber) 
which  serves  to  protect  the  other  constituents  of  the  flour 
from  the  action  of  the  various  juices. 


Influence  of  Various  Factors  on  Digestion     123 

124.  Relish  for  food.  —  This  involves  two  elements, 
the  vigor  of  appetite  and  the  attractiveness  of  the  food  in 
appearance  and  taste.     When  a  person  is  hungry,  in  other 
words,  has  a  "  good  appetite  "  and  the  food  meets  his  ap- 
proval in  its  kind  and  in  the  way  it  is  prepared,  the  psychic 
condition  is  favorable  to  abundant  secretions  in  the  diges- 
tive tract.     When,  on  the  other  hand,   the  appetite  is 
"  poor  "  or  the  food  is  distasteful,  the  necessary  activity 
of  the  secretory  glands  receives  no  such  stimulus.     Forced 
nutrition  does  not  conform  to  the  best  conditions  for  effi- 
cient nutrition.     Unskillful   or  slovenly   cooking,   or  an 
unwise  selection  of  food  may  neutralize  a  vigorous  appe- 
tite, or  even  breed  dyspepsia. 

125.  The   amount   eaten.  —  The   evidence   concerning 
the  effect  of  the  amount  eaten  at  one  meal  upon  the 
completeness  of  digestion  is  somewhat  conflicting,   but 
indicates  that  a  full  meal  is  somewhat  less  perfectly  digested 
than  when  food  is  taken  sparingly.     Snyder1  found  this 
to  be  so,  though  his  results  were  not  uniform.     Sherman2 
found  a  slight  difference  in  protein  digestion  in  favor  of  the 
restricted  diet.     It  is  fair  to  assume  that  with  heavy  eating 
the  completion  of  digestion  would  require  longer  than 
when  but  little  food  is  to  be  acted  upon.     Nevertheless, 
there  is  no  evidence  to  show  that  with  normal  digestion 
there  is  any  large  amount  of  waste  when  food  is  taken  in 
generous,  but  reasonable,  amounts. 

126.  Effect  of  work.  —  It  is  quite  generally  agreed  on  the 
basis  of  considerable  experimental  evidence  that  even  severe 
labor  does  not  depress  digestion.     In  other  words,  a  man  at 
rest  does  not  digest  his  food  differently  than  when  at  work. 

»Bul.  101,  O.E.S.,  p.  64.  2  Bui.  121,  O.E.S.,  p.  47. 


124  Principles  of  Human  Nutrition 

127.  Influence   of  accessory  articles  of  food.  —  These 
include   condiments,    flavors,   and   stimulants  which   are 
used,  not  for  their  food  value,  which  is  small,  but  as  a 
means  of  rendering  food  more  attractive  to  the  taste.     It 
cannot  be  said  that  these,   including  alcoholic   drinks, 
when  used  in  reasonable  quantity,  depress  digestibility. 
In  fact,  when  properly  used,  they  may,  and  probably  do, 
exert  a  favorable  influence  upon  digestion  by  promoting 
an  increased  flow  of  gastric  juice  through  the  psychic  effect 
of  a  pleasing  taste  and  through  their  reaction  on  the 
stomach  membranes.     Physicians   use  condimental  sub- 
stances to  excite  the  secretions  in  cases  of  weak  digestion. 
The  essential  conditions  of  good  digestion  do  not  justify 
the  prevalent  excessive  and  growing  demand  for  such 
condiments  as  the  peppers,  garlic,  mustard  and  vinegar 
the  long,  intemperate  use  of  which  produces  conditions  orr 
the  part  of  the  user  that  are  unnatural  and  ruinous  to  the 
stomach. 

128.  Influence  of  cooking  food.  —  In  considering  this 
factor,  it  is  necessary  to  understand  the  effect  of  heat  on 
different  classes  of  food.     As  we  have  learned,   certain 
proteins,  especially  the  albumins,  are  coagulated  and  har- 
dened by  heat,  even  at  a  temperature  considerably  below  the 
boiling  point.     Cooking  also  hardens,  that  is,  makes  more 
fibrous,  many  animal  tissues.     On  the  other  hand,   the 
effect  of  boiling  and  baking  upon  vegetable  tissue  is  to 
disintegrate    it,    liberate    starch    grains    from    their    cell 
inclosures,  and  make  them  available  to  the  action  of  the 
digestive  fluids,  more  or  less  dextrinize  starch,  and  in  some 
cases  cause  hydrolytic  changes,  as  when  in  the  cooking  of 
apples  and  other  fruits  the  pectins  are  changed  to  pectoses. 


Digestion  of  Different  Classes  of  Food       125 

These  facts  lead  to  the  conclusion,  which  is  also  sustained 
to  some  extent  by  experimental  evidence,  that  the  cooking 
of  meats  retards  digestion,  while  with  fruits  and  vegetables 
the  same  cause  accelerates  digestion.  The  advocates  of 
raw  vegetable  foods  should  appeal  only  to  persons  with 
strong  digestive  powers.  That  such  foods  promote  diges- 
tion as  compared  with  those  that  are  cooked,  in  the  light 
of  existing  knowledge  is  an  absurd  proposition. 

129.  Influence    of   individual    peculiarities.  —  It    is   a 
fact  of  common  experience  that  certain  persons  do  not 
comfortably  digest  certain  foods,  whatever  may  be  the 
ultimate  proportion  that  is  digested.     Definite  and  proven 
explanations  of  this  fact  are  not  available.     It  is  not 
improbable  that  a  mental  attitude  toward  a  given  food 
sometimes  has  its  influence,   although  this   can   hardly 
explain  why  certain  individuals  are  made  uncomfortable 
from  eating  strawberries  or  pork,  or  some  other  food. 
This  may  be  due  to  an  enzym  deficiency  in  some  part  of 
the  digestive  tract,  or  to  a  peculiar  reaction  upon  the 
individual  of  particular  compounds  present  in  the  offend- 
ing food ;  but  these  suggestions  are  speculative. 

130.  The   extent  to   which   different  classes   of   foods 
are  digested.  —  A  large  amount  of  experimenting  shows 
that  the  following  are  approximately  the  proportions  of 
the  nutrients  that  are  digested  in  the  different  classes  of 
foods.     These  figures  refer  to  apparent  digestibility  and 
not  to  actual.     If  the  metabolic  products  in  the  feces  were 
accounted  for,  the  proportions  would  be  higher,  especially 
for  protein.     The  satisfactory  separation  of  the  real  un- 
digested portion  of  the  food  from  the  accompanying  waste 
products  is  not  yet  accomplished. 


126 


Principles  of  Human  Nutrition 


TABLE    XXI 


KIND  OF  FOOD 

PROTEIN 

CARBO- 
HYDRATES 

FATS 

Meats  and  fish        

Per  Cent 
97 

Per  Cent 

Per  Cent 
95 

Esss 

97 

Q^J 

Dairy  products  

97 

98 

95 

Animal  foods  (mixed  diet)    .     .     . 
Cereals       

97 

85 

98 
98 

95 
95 

78 

97 

°/0 

Sugars  

98 

Starches     

98 

83 

95 

QO 

Fruits    

85 

90 

QO 

Vegetable  foods  (mixed  diet)     .  '  '.  . 
Total  food  (mixed  diet)    .... 

84 
92 

97 
97 

90    (' 
95 

CHAPTER  VI 

THE    DISTRIBUTION    AND     TRANSFORMA- 
TIONS OF   THE  DIGESTED  FOOD 

THE  digested  food,  after  absorption,  all  passes  into  the 
blood,  either  directly  or  indirectly,  and  mixes  with  it. 
The  materials  which  are  to  serve  the  purposes  of  nutrition 
are  now  taken  up  by  a  stream  of  liquid  that  is  in  constant 
motion  throughout  the  minutest  divisions  of  every  part 
of  the  animal.  Flowing  in  regular  channels,  the  blood 
reaches  not  only  the  bones  and  muscular  tissues,  but  it 
passes  through  several  special  organs  and  glands,  where  the 
nutrients  it  is  carrying  and  certain  of  its  own  constituents 
meet  with  profound  changes.  It  is  here  that  we  discover 
the  manner  in  which  food  is  applied  to  use,  and  what  are 
some  of  the  transformations  which  the  proteins,  carbohy- 
drates, and  fats  undergo  in  performing  their  functions. 

In  order  to  follow  intelligently  this  most  interesting 
phase  of  nutrition,  we  must  know  something  of  the  blood 
and    of   the    organs  —  the   lungs,  liver,   and   kidneys  — 
through  which  it  passes. 

A.    THE  BLOOD 

The  blood,  when  in  a  fresh  state,  is  apparently  colored 
and  opaque,  but  if  a  minute  portion  is  examined  with  a 
microscope,  it  is  seen  to  be  a  comparatively  clear  liquid  in 

127 


128 


Principles  of  Human  Nutrition 


which  float  numerous  reddish  disk-like  bodies  known 
as  corpuscles,  also  blood  plates  and  blood  granules.  These 
bodies  give  to  the  blood  its  bright  red  color.  The  liquid 

in    which    they 
are    suspended, 
£&&  a    clear    amber 

yellow    liquid, 
is     called    the 


puscles  are  not- 
mere  masses  (of 
unformed  mat- 
ter, but  they  are 
minute  bodies 
having  a  defi- 
nite form  and 
structure.  They 
make  up  from 
35  to  40  per  cent 
of  the  blood,  and 
contain  over  30 
per  cent  of  dry  matter.  This  dry  matter  consists  mostly 
of  haemoglobin,  a  compound  that  is  peculiar  to  the  blood, 
and  equips  it  for  one  of  its  most  important  offices. 

132.  Haemoglobin.  —  Haemoglobin,  as  before  stated, 
is  made  up  of  a  protein  (globin),  and  a  coloring  matter 
(haematin),  in  the  latter  of  which  is  combined  a  definite 
proportion  of  iron.  The  peculiar  property  of  this  com- 
pound, which  renders  it  so  useful  a  constituent  of  the 


FIG.  8.  —  Red  and  white  corpuscles  of  blood  (mag- 
nified). A,  red  corpuscles  ;  a,  a,  white  corpus- 
cles ;  B,  C,  D,  red  corpuscles,  much  magnified  ; 
F,  G,  white  corpuscles,  much  magnified. 


The  Blood  129 

blood,  is  its  power  of  taking  up  oxygen  and  holding  it  in  a 
loose  combination  until  it  is  needed  for  use  throughout 
the  body.  When  thus  charged,  it  is  known  as  oxyhse- 
moglobin.  Because  of  this  function  of  their  most  promi- 
nent constituent,  blood  corpuscles  become  the  carriers  of 
oxygen  to  all  parts  of  the  body.  They  are  also  concerned 
in  gathering  up  one  of  the  waste  products  of  the  nutritive 
changes,  viz.,  carbon  dioxid,  which  is  conveyed  by  them  in 
loose  chemical  combination  to  the  point  where  it  may  be 
thrown  off  from  the  body.  Hsematin  may  also  unite  with 
other  compounds,  as,  for  instance,  carbon  monoxid, 
which  displaces  and  excludes  oxygen  and  is  disastrous  in 
its  effects. 

133.  Leucocytes.  —  The   blood   also   contains   amoeba- 
like  bodies  know  as  •  white  corpuscles,  that  are  variable  in 
shape  and  constantly  changing  in  form.     These  are  some- 
times called  leucocytes,  and  are  regarded  as  having  an 
important  function.     They  may    increase  with  extraor- 
dinary   rapidity,   especially  around  centers    of    infection 
and  inflammation,  and  it  is  regarded  as  proven  that  they 
endeavor  to  destroy  foreign  bodies  in  the  blood  and  also 
render  harmless  the  injurious  products  coming  from  the 
activity  of  micro-organisms.     They  evidently  have  other 
functions  not  well  understood,  for  it  is  noticed  that  they 
accumulate  in  large  numbers  during  intestinal  digestion. 
Very  likely  they  act  as  a  means  of  transportation,  and 
they  probably  pla}7  some  part  in  metabolism  in  accom- 
plishing certain  exchanges  of  nutrient  substances. 

134.  The  plasma.  —  The  plasma  is  about  nine-tenths 
water,  so  that  it  easily  holds  in  solution  whatever  soluble 
nutrients  are  discharged  into  it  from  the  alimentary  canal. 


130  Principles  of  Human  Nutrition 

Among  its  constituents  are  found  members  of  all  the  classes 
of  compounds  that  are  important  in  this  connection,  — 
ash,  protein,  carbohydrates,  and  fats.  The  proportion  of 
ash  is  about  1  per  cent,  three-fourths  of  it  being  common 
salt,  and  the  remainder  consisting  of  phosphoric  acid, 
lime,  and  other  important  mineral  compounds.  The  solid 
matter  of  the  plasma  is  rich  in  proteins,  including  the 
fibrinogen,  which  is  the  mother  substance  of  fibrin,  and 
several  albumins  and  globulins.  These  proteids  make  up 
about  80  per  cent  of  the  total  dry  substance  of  the  plasma. 
Sugar  and  fats  are  also  present,  their  proportions  varying 
somewhat  with  the  extent  to  which  they  are  being  absorbed 
from  the  digestion  of  food.  In  fact,  the  blood  carries\not 
only  its  characteristic  and  permanent  constituents,  but 
also  the  nutrients  absorbed  from  the  alimentary  canal. 
It  is  evident  that  the  blood  is  charged  with  those  materials 
which  we  recognize  as  necessary  to  the  construction  and 
maintenance  of  the  animal  body.  The  plasma  also  con- 
stantly contains  very  small  proportions  of  the  end  products 
of  metabolism,  such  as  urea  and  uric  acid  and  waste  bile 
products  which  are  being  transported  to  the  points  of 
excretion.  It  also  holds  in  solution,  or  as  carbfnates, 
some  of  the  carbon  dioxid  gathered  up  in  the  circulation 
of  the  blood  through  the  tissues. 

B.    THE  HEART 

In  quantity,  the  blood  is  from  3  to  4  per  cent  of  the 
total  weight  of  the  human  body.  It  is  contained  in  the 
heart  and  in  two  sets  of  vessels,  one  set  called  the  arteries, 
leading  from  the  heart  by  various  ramifications  to  all 


The  Heart 


131 


Principles  of  Human  Nutrition 


parts  of  the  body,  and  the 
other  set  called  the  veins, 
leading  from  all  parts  of  the 
body  back  to  the  heart. 

135.  Circulation. — Through 
these  vessels  the  blood  is 
moving  in  a  constant  stream, 
which  we  call  the  circulation. 
It  does  not  move  of  itself, 
but  is  forced  along  by  a  very 
powerful  pump,  the  heart. 
This  is  a  highly  muscular 
organ  divided  into  four  cham- 
bers, which  are  separated  by 
valves  and  partitions,  the  two 
upper  chambers  being  called 
the  right  and  left  auricles, 
and  the  two  lower,  the  right 
and  left  ventricles.  The  right 
auricle  is  above  the  right 
ventricle,  and  is  separated 
from  it  by  a  valve,  and  the 
same  is  true  of  the  left  auri- 
cle and  ventricle.  Out  of  the 
left  ventricle,  the  blood  is 
pumped  into  the  arteries,  and 
after  reaching  the  arterial 

FIG.  10.  —  Diagram  of  circulation. 
1,  heart;  2,  lungs;  3,  head  and 
upper  extremities ;  4,  spleen ;  5, 
intestine  ;  6,  kidney  ;  .  7,  low.er  ex- 
tremities ;  8,  liver.  (COLLINS.) 


The  Lungs  133 

capillaries  throughout  the  entire  body,  it  passes  from 
these  into  the  smallest  divisions  of  the  veins  and  comes 
back  to  the  heart  along  the  venous  system,  entering  the 
right  auricle.  It  is  then  carried  to  the  lungs  by  way 
of  the  right  ventricle  and  is  returned  to  the  left  auricle 
to  be  sent  to  the  left  ventricle,  and  from  there  to  again 
start  on  its  journey  through  the  body.  As  we  shall 
see,  the  arterial  blood  carries  to  the  body  food  nutri- 
ents and  oxygen,  and  the  venous  blood  brings  back 
the  wastes.  The  principal  facts  pertaining  to  the  blood 
and  its  circulation  have  been  reviewed  in  this  simple 
manner  as  an  aid  to  the  discussing  of  other  considerations 
somewhat  pertinent  to  our  subject. 

136.  Entrance  of  nutrients.  —  The  nutrients,  as  pre- 
pared for  use  by  digestion,  enter  the  blood  on  its  return  flow 
to  the  heart,  coming  into  the  venous  cavity  by  way  of  the 
hepatic  (liver)  vein  and  the  thoracic  duct  as  previously 
described.  When,  therefore,  the  right  side  of  the  heart  is 
reached,  a  new  accession  of  food  material  is  on  its  way  to 
sustain  the  various  functions  of  nutrition. 

We  are  more  interested  in  the  object  of  blood  circulation 
than  we  are  in  its  mechanism.  Somehow  the  digested 
food  disappears  into  these  constantly  moving  blood  cur- 
rents, and  the  only  evidence  of  its  effect  which  comes  to 
us  from  ordinary  observation  is  the  warmth,  motion,  and 
perhaps  growth,  of  the  animal  that  is  nourished. 

C.    THE  LUNGS 

The  first  point  where  important  changes  occur  is  the 
lungs.  Here  the  blood  loses  the  purplish  hue  which  it 
always  has  after  being  used  in  the  body  tissues,  and  takes 


134 


Principles  of  Human  Nutrition 


on  a  bright  scarlet,  —  a  phenomenon  that  is  more  easily 
understood  when  we  understand  the  lung  structure. 

137.   Object   of    breathing.  —  Breathing  is  a  matter  of 
common  experience.     We  all  know  how  air  is  drawn  into 


BPPER  LOBE 


RIGHT  LUNQ 


LEFT  LUNG 


FIG.  11.  —  Air  tubes  of  lungs.     (GERRISH.) 

the  lungs  at  regular  intervals,  and  equivalent  volumes  of 
modified  air  being  as  regularly  forced  out.  The  mechan- 
ism of  respiration  (breathing)  we  will  not  discuss  at  length. 
It  will  aid  us,  however,  if  we  know  that  the  passage  which 
the  air  follows  to  and  from  the  lungs,  the  trachea  (wind- 


The  Use  of  Food  135 

pipe),  divides  into  two  branches,  one  to  each  lung,  and 
these  divide  and  subdivide  until  they  branch  into  numerous 
fine  tubes.  Each  of  these  tubes  ends  in  an  elongated  dila- 
tion which  is  made  up  of  air  cells  opening  into  a  common 
cavity.  These  cells  are  so  numerous  in  the  lung  tissues 
that  only  a  very  thin  wall  separates  adjoining  ones,  and 
in  this  wall  are  carried  the  capillaries  or  fine  divisions  of 
the  blood-vessels  leading  from  the  heart.  This  arrange- 
ment permits  the  (venous)  blood,  as  it  flows  along,  to  take 
up  oxygen  from  the  respired  air  and  transfer  certain  wastes 
into  the  lung  cavities,  and  thus  be  made  ready  to  go  back 
to  the  body  carrying  a  joint  load  of  digested  food  and  of 
oxygen  that  is  held  in  combination  with  the  hsematin.  Of 
course  the  air  that  passes  out  of  the  lungs  is  less  rich  in 
oxygen  than  when  it  ,was  taken  in,  and  there  have  been 
added  to  it  certain  materials  which  we  will  notice  later. 

It  is  easily  understood  from  these  facts  that  respiration 
stands  in  a  fundamental  relation  to  nutrition.  The  lungs 
are  to  the  body  what  the  draft  is  to  the  furnace.  Food 
can  no  more  be  used  without  the  supply  of  oxygen  through 
the  lungs  than  can  coal  be  burned  without  an  access  of  air 
to  the  fuel  box. 

D.    THE  USE  OP  FOOD 

The  revivified  (arterial)  blood  now  passes  to  all  parts  of 
the  body  and  is  brought  into  the  most  intimate  relation 
with  the  minutest  portion  of  every  tissue.  Several  things 
happen  in  the  course  of  time,  all  of  which,  whether  the 
combination  or  cleavage  of  food  compounds,  or  the  oxi- 
dations that  result  in  complete  combustion,  are  brought 
about  by  the  protoplasmic  activity  of  the  cells  of  which 
the  body  tissues  are  an  aggregation. 


136  Principles  of  Human  Nutrition 

138.  Builds  tissue.  —  In  the  first  place,  the  new  supply 
of  nutritive  substances  is  used  by  the  living  cells  in  a  way 
we  do  not  wholly  understand,  to  rebuild  worn-out  tissue 
and  to  form  new  growth.     With  the  young  animal,  much 
material  is  appropriated  in  the  latter  ,way.     In  the  case 
of  mammals,  there  is  furnished  to  the  mammary  gland  the 
nutrients  out  of  which  the  milk  is  formed  through  the 
special  activities  of  that  gland. 

139.  Function  of  oxygen.  —  Moreover,  it  is  in  the  tissues 
that  the  oxygen  which  was  taken  up  in  the  lungs  is  used 
to  slowly  oxidize  a  portion  of  the  food.     This  combustion 
is  believed  not  to  take  place  by  contact  of  the  oxygen  and 
nutrients  in  the  blood-vessels,  but  it  occurs  through  cell 
activity    by   progressive    steps    throughout    the    minute 
divisions  of  the  muscles  and  other  tissues  of  the  body. 
The  tissue  cells  undoubtedly  obtain  their  energy  from 
oxidation  of  the  nutriment  furnished  to  them.     Notwith- 
standing this  oxidation  may  be  very  gradual  and  occupy 
much  time,  its  ultimate  products  are,  for  the  most  part, 
similar  to  those  which  result  from  the  rapid  combustion 
of  fuel.     In  the  fireplace,  starch,  sugar,  cellulose,  fats,  and 
similar  bodies  would  be  burned  to  carbonic  acid  and  water, 
and  this  is  what  takes  place  in  the  animal  to  the  extent 
that  these  nutrients  are  not  used  constructively. 

140.  Protein  not  wholly  oxidized.  —  When  the  protein 
is  not  stored  as  such,  but  is  broken  up,  the  result  in  the 
animal  is  somewhat  different  from  that  in  the  furnace, 
because  in  the  former  the  oxidation  is  not  complete.     In 
the  animal,  the  proteins  are  partially  oxidized  to  carbonic 
acid  and  water,  but  a  portion  of  their  substance  passes 
from  the  body  principally  in  the  form  of  urea  and  uric 


Elimination  of  Wastes  137 

acid,  which  are  the  prominent  constituents  of  urine. 
These  compounds  carry  with  them  a  certain  proportion  of 
carbon  and  hydrogen  which,  in  ordinary  fuel  combustion, 
would  more  fully  unite  with  oxygen.  The  heat  produc- 
tion from  protein  is  therefore  less  in  the  animal  than  in 
the  furnace. 

Oxidations  in  the  human  body  are  continuous,  but  not 
uniform.  They  vary  with  the  mass,  age,  and  habits  of 
the  individual,  with  the  exercise  the  individual  is  taking, 
and  with  the  amount  of  food  that  must  be  disposed  of. 
The  quantity  of  oxygen  needed  is  therefore  variable, 
and  when  the  demand  for  it  with  a  given  individual  is 
largely  increased,  the  heart  pumps  faster,  more  blood 
passes  through  the  lungs,  the  breathing  is  more  rapid,  and 
the  supply  of  oxygen  is  in  this  way  augmented. 

E.     ELIMINATION  OF  WASTES 

The  various  waste  products  from  this  combustion  of  the 
digested  nutrients  and  from  the  breaking  up  of  the  proteins 
within  the  animal  body  evidently  must  be  disposed  of  in 
some  manner.  If  not  eliminated  from  the  body,  they 
would  cause  results  of  a  most  serious  character,  as,  for 
instance,  when  an  accumulation  of  urea  in  the  blood  pro- 
duces ursemic  poisoning.  The  blood,  therefore,  not  only 
carries  to  the  tissues  the  necessary  nutrients  and  oxygen, 
but  it  has  laid  upon  it  the  burden  of  taking  into  its  currents 
the  waste  products  of  combustion  and  growth,  and  carry- 
ing them  to  the  points  where  they  are  thrown  off. 

141.  Urea.  —  One  of  the  branches  of  the  arterial  system 
of  blood-vessels  runs  to  the  kidneys,  and,  by  repeatedly 
rebranching,  traverses  all  their  substance.  The  main 


138  Principles  of  Human  Nutrition 

function  of  the  kidneys  is  to  secrete  the  urine,  a  liquid  in 
which  all  the  waste  nitrogen  from  the  digested  protein 
finds  its  way  out  of  the  body  in  the  form  of  urea  and  other 
nitrogen  compounds.  The  blood  that  enters  them  carries 
with  it  the  urea  and  uric  acid  which  have  resulted  from 
a  breaking  down  of  protein,  and,  in  a  most  wonderful 
manner,  these  compounds  are  filtered  out  so  that  they  are 
not  present  in  the  outgoing  blood. 

142.  Mineral    compounds.  —  The   mineral   ingredients 
of  the  food  in  excess  of  storage  in  the  body  are  excreted 
both  through  the  kidneys  and  in  the  feces.     Compounds 
of  potassium  and  sodium  appear  almost  wholly  in  the 
urine.     Phosphorus,  calcium,  and  magnesium  are  divided 
between  the  urine  and  feces,  the  two  former  being  more 
largely  excreted  by  way  of  the  intestines,  while  practically 
all  the  iron  goes  out  by  way  of  the  feces. 

143.  Carbon    dioxid.  —  The    carbon    dioxid    must    in 
some  way  also  be  eliminated  from  the  body.     This  is  not 
accomplished  to  any  extent  until  the  venous  blood  con- 
taining it  reaches  the  lungs,  where  it  is  exchanged  for 
a  new  supply  of  oxygen  and  passes  off  in  the  expired 
air.     In  the  case  of  man,  the  air  "  breathed  out  "  is  nearly 
a  hundred  times  richer  in  carbonic   acid  than  the  air 
"  breathed  in." 

144.  Water.  —  Water  may  be  regarded  from  one  point 
of  view  as  a  waste,  for  it  is  produced  in  the  oxidation  of 
the  food,  and  this  passes  off  from  the  lungs  as  vapor, 
through  the  skin  as  sensible  or  insensible  perspiration,  and 
in  considerable  quantities  through  the  kidneys.     Benedict 
and  Carpenter  have  shown,  on  the  basis  of  a  large  number  of 
determinations,  an  average  loss  of  960  grams  of  water  from 


The  Liver  139 

the  lungs  and  skin  by  a  person  at  rest,  during  twenty-four 
hours ;  a  little  less  than  two-thirds  of  this  loss  coming  from 
the  surface  of  the  body.  This  "  insensible  perspiration  " 
is  60  per  cent  as  much  as  the  water  excretion  through  the 
kidneys.  A  man  at  hard  work  may  lose  several  times  as 
much  water  from  the  lungs  and  skin  as  through  the  kidneys. 
To  summarize,  it  may  be  said  that  the  blood  is  constantly 
undergoing  gain  and  loss.  The  gain  comes  from  the  food 
(including  water  and  oxygen),  and  the  loss  consists  of 
urea,  carbonic  acid,  and  water  given  off  through  various 
channels. 

F.    THE  LIVER 

One  part  of  the  arterial  system  of  blood-vessels  runs  to 
the  stomach  and  intestines,  and  is  distributed  over  their 
walls  in  fine  divisions.  These  connect  with  the  capillaries 
of  the  portal  vein,  which  leads  to  the  liver.  During  this 
passage  of  the  blood  from  one  system  to  the  other,  part  of 
the  digested  food  is  taken  up.  Now  it  is  very  evident 
that  the  quantity  of  material  thus  absorbed  must  vary 
greatly  at  different  times  according  to  the  nature  and 
amount  of  food  supply  and  the  activity  of  the  digestive 
processes.  If,  therefore,  the  blood  from  the  alimentary 
canal  was  allowed  to  pass  directly  into  the  general  circula- 
tion, the  supply  to  the  tissues  of  the  nutrients,  especially 
the  carbohydrates,  would  be  very  uneven. 

145.  Function  of  liver.  —  Just  here  comes  in  a  liver 
function.  In  that  organ  there  is  found  a  starch-like 
body  known  as  glycogen  (see  p.  73),  which  appears  in  in- 
creased quantity  following  the  abundant  absorption  of 
sugar  from  the  intestines.  It  is  believed,  because  of  this 
and  other  facts,  that  the  liver  acts  as  a  regulator  of  the 


FIG.  12.  —  Portal  system  of  veins.     Showing  how  absorbed  nutrients  are  collectec 
intestinal  tract  and  carried  to  liver  by  portal  vein. 


The  Liver  141 

carbohydrate  supply  to  the  general  tissues  of  the  body, 
storing  a  temporary  excess  of  the  sugar  in  the  form 
of  glycogen,  which  is  gradually  given  up  to  the  general 
circulation  as  it  is  needed  after  first  being  transformed 
back  to  sugar.  Glycogen  is  also  stored  in  the  muscles,  in 
an  amount  equal  to  or  greater  than  that  in  the  liver. 


CHAPTER   VII 
THE  FUNCTIONS   OF   FOOD   COMPOUNDS 

A.    SCIENTIFIC  METHODS  OF  INQUIRY 

THE  discussion  of  human  nutrition  on  a  scientific  basis 
requires  an  understanding  of  what  are  the  physiological 
needs  of  the  human  organism  under  various  conditions 
and  how  these  may  be  met  most  efficiently  and  econom- 
ically. Before  stating  present  views  of  the  functions  of 
the  several  nutrients,  it  will  be  well  to  gain  some  concep- 
tion of  how  we  have  arrived  at  the  knowledge  upon  which 
our  conclusions  are  based,  for  such  a  consideration  of 
methods  will  doubtless  strengthen  confidence  in  the  con- 
clusions. 

146.  A  determination  of  the  elements  essential  to  the 
construction  of  the  human  body.  —  Definite  information 
as  to  the  constructive  elements  of  the  tissues  of  the  human 
body  has  been  obtained  by  chemical  analysis.  It  is  a  fair 
assumption  that  whatever  is  uniformly  found  present  in 
a  normally  nourished  organ  or  tissue  is  essential  either  to 
its  construction  or  welfare.  To  be  sure,  the  human  body 
may  retain  certain  substances  in  quantities  that  are  not 
only  unnecessary,  but  injurious,  as,  for  instance,  arsenic; 
but  when  a  salt  of  potassium  is  found  in  the  muscular  tissue 
in  practically  constant  proportions  under  all  conditions 

142 


Methods  of  Inquiry  143 

of  nourishment,  it  is  fair  to  assume  that  normal  muscles 
could  not  exist  without  it.  Indeed,  we  know  that  the  ab- 
sence of  certain  elements  would  make  impossible  the  pres- 
ence in  the  human  body  of  those  compounds  that  are 
essential  to  its  very  existence. 

147.  Methods  of  ascertaining  the  functions  of  the 
various  nutrients  and  the  needs  of  the  human  body  under 
varying  conditions.  —  Our  understanding  of  the  functions 
of  the  food  compounds  and  of  the  most  efficient,  and  physi- 
ologically most  economical,  administration  of  dietaries 
under  varying  conditions  is  still  incomplete.  The  exact 
knowledge  we  do  possess  is  the  result  of  many  years  of 
laborious  investigation.  We  still  lack  much  essential 
information  concerning  the  special  physiological  relations 
and  reactions  of  the  individual  compounds  found  in  human 
food,  but  the  general  metabolism,  or  food  exchange  and 
use,  in  the  animal  organism  is  now  sufficiently  well  under- 
stood to  admit  of  many  safe  and  important  conclusions. 

Children  and  adults  who  are  living  under  varying  con- 
ditions of  age,  environment,  and  activity  consume  in- 
dividually a  given  amount  of  food  daily.  Certain  ques- 
tions arise.  Is  the  food  sufficient  in  quantity?  Is  it 
of  the  right  kind  from  the  physiological  point  of  view ;  that 
is,  are  the  nutrients  of  the  right  kind  and  in  the  right  pro- 
portion? A  general  practical  answer  to  these  two  ques- 
tions might  be  found  in  an  observation  as  to  the  health  and 
physical  status  of  the  individual,  which  are  the  facts  of 
ultimate  importance.  The  laws  of  nutrition  cannot  be 
established  by  such  general  observations,  however.  Even 
changes  in  body  weight  are  not  a  safe  basis  for  concluding 
whether  a  given  diet  is  meeting  the  nutritive  demands  of 


144  Principles  of  Human  Nutrition 

a  given  individual.  A  loss  of  fat  may  be  replaced  by  a 
gain  of  water.  It  has  been  shown  also  *  "  that  a  change 
from  a  diet  poor  in  carbohydrates  to  one  rich  in  carbo- 
hydrates is  accompanied  by  a  considerable  retention  of 
water  in  the  tissues  of  the  body."  In  these  ways  we  learn 
nothing  of  processes  or  how  the  physiological  needs  of 
the  individual  must  be  met,  and  we  could  not  reason  from 
one  case  of  apparently  successful  nourishment  to  know 
how  to  meet  the  needs  of  another  individual  under  entirely 
different  conditions. 

148.  Necessary  measurements.  —  It  is  clear  that  first 
of  all  it  is  necessary  to  measure  both  the  income  of  the 
body,  that  is,  the  food  plus  water  and  oxygen,  and  also  the 
outgo,  that  is,  the  excretions  which,  as  we  have  learned,  are 
practically  all  included  in  what  passes  out  through  the 
lungs,  the  skin,  the  kidneys,  and  in  the  feces.  We  must 
do  this  not  only  that  we  may  determine  whether  with  a 
given  diet  the  individual  is  losing  or  gaining  body  sub- 
stance, but  we  must  also  in  this  way  ascertain  in  what  the 
body  gain  or  loss  consists,  whether  of  protein  or  of  fat. 
In  being  able  to  measure  the  balance  in  this  way,  it  is 
possible  to  determine  what  is  the  minimum  amount  of  food 
that  will  maintain  an  individual  under  given  conditions 
of  activity  without  loss  of  body  substance,  and  also  whether 
a  given  ratio  of  nutrients  is  efficient.  Indeed,  it  is  by  this 
method  that  we  have  learned  how  and  to  what  extent  the 
body  substance  is  utilized  to  supplement  food  deficiencies, 
whether  of  kind  or  quantity.  It  is  also  possible  to  de- 
termine the  extent  to  which  nutrients  of  one  class  may  be 

1  "  Metabolism  and  Energy  Transformations  of  Healthy  Man  during 
Rest,"  Benedict  and  Thome,  p.  110. 


Respiration  Calorimeter  145 

substituted  for,  or  conserve,  those  of  another  class,  or 
what  is  the  effect  of  omitting  from  the  diet  all  of  one  class 
of  compounds. 

149.  How  measurements  are  made.  Respiration  cal- 
orimeter. —  Let  us  consider  more  in  detail  how  it  is  pos- 
sible to  arrive  at  a  balance  between  the  income  and  outgo 
of  the  body.  It  is  a  mere  matter  of  weighing  and  chem- 
ical analysis  to  ascertain  what  enters  the  body  in  the  food 
and  drink,  —  the  quantities  of  carbon,  nitrogen,  phos- 
phorus, sulfur,  and  all  the  other  elements.  Recently 
it  has  become  possible  to  measure  the  oxygen  consumed 
in  breathing.  The  food,  drink,  and  oxygen  constitute  the 
income.  Of  the  outgo,  viz.,  the  feces,  urine,  carbon  dioxid 
from  the  lungs,  and  water  from  the  lungs  and  skin,  the  feces 
and  urine  can  be  weighed  and  analyzed,  as  is  done  with 
the  food.  For  measuring  the  carbon  dioxid  and  water 
excreted,  a  special  apparatus  has  been  devised,  which  also 
now  measures  the  oxygen  consumed  and  heat  given  off. 
This  apparatus  is  known  as  a  respiration  calorimeter.  By 
means  of  the  respiration  apparatus  it  is  possible  to  meas- 
ure, not  only  the  gaseous  excreta  delivered  to  the  air  or 
the  respiration  chamber,  but  also  to  discover  what  par- 
ticular nutrients  are  being  oxidized  at  any  given  time. 
This  is  done  by  determining  what  is  known  as  the 
respiratory  quotient,  which  is  obtained  by  dividing  the 
volume  of  carbon  dioxid  evolved  by  the  volume  of 
oxygen  used.  If  a  carbohydrate  alone  is  oxidized,  the 
two  volumes  are  equal  and  the  quotient  is  1.00.  If  fat 
alone  is  being  burned,  the  carbon  dioxid  is  less  in  vol- 
ume than  the  oxygen,  and  the  quotient  is  approximately 
.70.  When  a  mixture  of  fat  and  carbohydrates  is  being 


146  Principles  of  Human  Nutrition 

utilized,  the  quotient  will  range  somewhere  between  1.00 
and  .70  and  the  relative  proportion  of  these  two  classes 
of  nutrients  that  are  undergoing  oxidation  can  be  deter- 
mined by  calculation. 

150.  Food  balances.  —  The  fundamental  facts  upon 
which  a  food  balance  is  based  are  the  following:  The 
general  balance  of  gain  or  loss  of  tissue  is  obtained  by 
comparing  the  income  and  outgo  of  carbon.  All  organic 
compounds,  whether  in  the  plant  or  animal,  contain  carbon, 
and  cannot  be  formed  without  it.  If,  therefore,  the  carbon 
taken  into  the  body  is  more  than  that  given  off  through 
the  various  channels,  it  is  proof  that  the  body  substance 
has  increased.  If  the  balance  is  the  other  way,  there  has 
been  a  loss  of  body  tissue. 

It  is  possible  to  know  the  kind  of  tissue  that  is  lost  or 
gained.  All  the  nitrogen  excreted  from  the  body  passes 
out  in  the  urine  and  feces,  that  in  the  urine  coming  from 
the  digested  protein.  No  protein  tissues  can  be  formed 
without  the  use  of  nitrogen,  and  no  other  tissues  require 
its  retention.  If,  therefore,  the  body  retains  nitrogen, 
it  is  evidence  that  muscular  tissue  or  some  other  form  of 
nitrogenous  substance  has  been  deposited.  If  at  the  same 
time  the  body  has  retained  more  carbon  than  would  be 
required  for  the  increase  of  protein  tissue,  then  it  is  neces- 
sary to  conclude  there  has  been  also  a  deposition  of  fat 
or  other  non-nitrogenous  material.  By  such  means  it  is 
possible,  for  instance,  to  discover  the  effect  of  a  given 
dietary  upon  protein  storage,  or  to  learn  if  a  change 
in  activity,  such  as  passing  from  rest  to  hard  work, 
causes  a  greater  utilization  of  protein,  or  whether  the  in- 
creased need  for  food  to  sustain  increased  labor  may  be 


The  Functions  of  Food  Compounds         147 

met  by  eating  more  carbohydrates.  The  ratio  in  which 
one  nutrient  may  replace  another  is  also  an  important 
consideration  that  the  respiration  calorimeter  has  made 
it  possible  to  study. 

151.  Energy  balance  and  use.  —  Very  delicate  modern 
apparatus  now  accurately  measures  the  potential  energy 
of  various  food  compounds ;  that  is,  the  energy  that  they 
give  up  in  the  form  of  heat  or  motion  when  burned.  The 
respiration  calorimeter  measures  the  heat  given  off  from 
the  human  body,  heat  being  the  end  product  of  all  vital 
activity.  This  may  be  done  with  the  subject  both  at  rest 
and  at  work.  If,  then,  by  the  metabolic  balance  it  is  shown 
how  much  food  has  been  oxidized  and  how  much  has  been 
retained,  conclusions  may  be  drawn  as  to  the  food  energy 
utilized  for  the  vital  processes  of  the  subject,  and,  by  taking 
such  measurements  with  the  subject  at  rest  and  doing 
different  amounts  of  work,  it  is  possible  to  learn  how  much 
food  is  needed  to  accomplish  a  given  amount  of  work. 
By  such  means  the  law  of  the  correlation  and  conservation 
of  energy  has  been  shown  to  hold  with  human  machines 
as  well  as  with  those  of  wood  and  iron. 

B.    THE  FUNCTIONS  OF  THE  NUTRIENTS 

The  digestion,  absorption,  and  distribution  of  food  are 
not  its  use,  —  they  are  the  preliminaries  necessary  to  use. 
Not  until  the  nutrients  have  been  converted  to  available 
forms  and  have  passed  into  the  blood  do  they  in  the 
slightest  degree  furnish  energy  or  building  material  to 
the  animal  organism.  We  have  followed  to  a  certain 
extent  the  chemical  changes  wrhich  the  digested  food 
suffers,  but  no  detailed  statements  have  been  made 


148  Principles  of  Human  Nutrition 

as  to  the  part  taken  by  each  class  of  nutrients  in  con- 
structing the  human  body  and  in  maintaining  its  com- 
plex activities. 

152.  Food  used  in  two  general   ways.  —  The  animal 
organism  uses  food  in  two  general  ways :    viz.,  for  con- 
structive purposes,  which  involve  the  building  or  repair 
of  tissue  and  the  formation  of  milk;  and  as  fuel  for  supply- 
ing different  forms  of  energy  mainly  through  oxidation  of 
the  food  nutrients.     The  tissues  which  are  to  be  formed 
are  of  several  kinds ;  principally  the  mineral  portion  of  the 
bone;   the  nitrogenous  tissue  of  the  muscles,  tendons,  skin, 
hair,  and  various  organs  and  membranes ;  and  the  deposits 
of  fat  which  are  quite  generally  distributed  throughout 
the  body  substance. 

153.  Forms  of  energy.  —  Energy  in  the  forms  in  which 
it  is  used  by  the  animal  organism  may  appear  as  muscular 
activity,  such  as  walking,  working,  breathing,  the  beating 
of  the  heart,  the  movements  of  the  stomach  and  intestines, 
as  heat,  and  as  chemical  energy  necessary  for  carrying 
on  digestion  and  other  metabolic  changes.     The  human 
body  is  certainly  the  seat  of  greatly  varied  and  complex 
constructive   and   destructive   activities,   which   are  sus- 
tained by  the  matter  and  potential  energy  of  the  food. 
How  this  is  done  we  do  not  fully  understand,  but  we  know 
many  facts  which  are  of  great  scientific  and  practical  im- 
portance and  which  must  be  consciously  or  unconsciously 
recognized  if  we  would  not  coihe  into  conflict  with  im- 
mutable laws. 

154.  Functions  of  water.  —  Water   fills  an  important 
place  in  the  nutrition  of  all  forms  of  life.     In  both  plants 
and  animals  it  acts  as  a  solvent  of  the  building  materials 


Functions  of  Mineral  Compounds          149 

which  it  carries  from  one  part  of  the  organism  to  another. 
It  also  serves  as  a  carrier  of  wastes,  particularly  those  ex- 
creted through  the  kidneys,  and  the  free  use  of  water  is 
recommended  as  promoting  thorough  cleansing  of  the  tis- 
sues. It  is  proper  to  speak  of  water  as  building  material 
for  the  animal  body,  for  it  is  an  abundant  constituent  of 
animal  tissue  and  takes  part  in  chemical  changes  such  as 
hydrolysis.  It  fills  an  essential  office  in  regulating  the 
heat  processes  of  the  body  through  varying  rates  of  evap- 
oration (see  p.  168). 

155.  Functions  of  the  mineral  compounds.  —  We  have 
learned  that  mineral  compounds  are  abundant  in  the  human 
body.  The  tissues,  the  blood,  digestive  fluids,  and  es- 
pecially the  body  framework,  contain  a  variety  of  these 
bodies,  which  are  as  essential  as  any  other  substances  to 
the  building  and  maintenance  of  the  animal  organism. 
Bone  formation  without  phosphoric  acid  and  lime  is  not 
possible,  and  to  deprive  the  gastric  juice  of  the  chlorine 
which  it  contains  would  be  to  destroy  its  usefulness. 
Sodium  salts  are  an  essential  part  of  the  bile,  iron  must  be 
supplied  to  the  hsematin  of  the  blood,  and  potassium  phos- 
phate is  always  present  in  muscular  tissue.  Children 
would  fail  to  develop  if  given  no  mineral  food,  and  adults, 
if  entirely  deprived  of  even  one  substance,  sodium  chloride, 
would  become  weak,  inactive,  and  finally  die.  Not  only 
must  the  growing  child  have  the  ash  compounds  for  con- 
structive purposes,  but  the  mature  man  must  be  supplied 
with  them  in  order  to  sustain  the  nutritive  functions.  It  is 
especially  true  of  mammalian  females,  which  store  com- 
binations of  phosphoric  acid,  lime,  and  potash  so  abun- 
dantly in  the  milk  that  they  must  have  an  adequate  sup- 


150  Principles  of  Human  Nutrition 

ply  of  these  substances.  Nothing  is  clearer  than  that  these 
materials  must  of  necessity  be  furnished  in  the  food.  They 
cannot  originate  in  the  animal  organism,  neither  can  carbon 
compounds  take  their  place. 

Mineral  compounds  evidently  have  important  offices 
outside  of  supplying  constructive  material.  Their  physio- 
logical influence  or  reactions  must  also  be  taken  into  ac- 
count. While  the  whole  subject  is  not  well  understood, 
abundant  evidence  exists  that  the  chemical  environment 
of  animal  tissues  has  an  important  influence  in  several 
directions.  It  has  been  shown  that  the  eggs  of  certain 
marine  fishes  multiply  (segment)  normally  only  in  water 
containing  a  mixture  of  certain  salts  of  a  certain  concen- 
tration. In  the  same  way  muscular  contractions  are 
greatly  influenced  by  the  salts  that  are  in  contact  with  the 
tissues.  Osmotic  pressure  or  the  rate  of  transfer  of  liquids 
in  the  animal  body  is  also  influenced  by  the  inorganic 
salts-  present.  Indefinite  as  our  knowledge  is,  it  is  quite 
evident  that  the  soluble  salts  of  calcium,  magnesium, 
potassium,  and  sodium  play  an  important  role  in  the  vital 
activities  of  the  animal  organism,  other  than  for  construc- 
tive purposes. 

156.  Phosphorus  and  brain  power.  —  It  was  at  one 
time  popularly  taught  that  phosphorus  has  a  special  re- 
lation to  brain  activity  and  because  fish  was  supposed  to 
contain  much  phosphorus  it  was  commonly  spoken  of  as 
"  brain  food."  As  a  matter  of  fact,  it  has  never  been  shown 
that  this  element  has  an  especial  relation  to  brain  activity, 
and,  moreover,  fish  is  no  richer  in  phosphorus  than  many 
other  foods,  such  as  meats,  milk,  cheese,  and  certain  grains 
(see  p.  387).  To  be  sure,  the  nerve  tissue  is  relative^  rich 


Functions  of  Protein  151 

in  phosphorus,  but  other  elements  are  just  as  essential 
to  the  structure  of  the  brain. 

157.  Foods    supplying    mineral    compounds.  —  Nature 
seems  to  have  adapted  our  needs  to  the  compounds  fur- 
nished by  the  natural  food  products,  such  as  the  cereal 
grains,  milk,  meat,  and  other  unmodified  materials,  as 
they  supply  a  complete  variety  of  the  needed  inorganic 
substances.     Milk,  which  is  the  exclusive  food  of  infants, 
is  especially  adapted  to  rapid  bone  formation.     It  is  only 
when  modified  (artificial)  foods  are  largely  eaten,  foods 
from  which  the  mineral  salts  have  been  extracted  by 
manufacturing  processes,  that  we  need  fear  a  deficiency  of 
the  necessary  mineral  compounds.      (See  pp.  210-211.) 

Much  is  written  about  the  proper  proportion  of  protein 
and  carbohydrate  in  the  food,  but  it  is  to  be  feared  that 
the  equally  critical  matter  of  the  supply  of  the  so-called 
mineral  ingredients  does  not  receive  attention  commen- 
surate with  its  importance. 

158.  Functions  of  protein.  —  While  there  are  at  present 
many  unsolved  problems  relative  to  the  nutritive  offices 
of  protein,  there  is  no  reasonable  doubt  that  the  food 
proteins  are  the  only  source  of  similar  substances  in  the 
animal  body.     This  is  equivalent  to  a  statement  that  from 
the  food  proteins  are  formed  the  muscles,  the  connective 
tissues,  the  skin,  hair,  and  the  major  part  of  the  tissues  of 
the  secretive  and  excretive  organs ;  in  short,  that  they  are 
the  source  of  a  large  proportion  of  all  the  working  parts 
of  the  human  body.     So  far,  scientific  research  has  not 
succeeded  in  demonstrating  that  a  protein  is  ever  syn- 
thesized (built  up  from  simple  compounds)  outside  of  the 
plant.     It  appears  that  bodies  of  this  class  must  come 


152  Principles  of  Human  Nutrition 

to  animal  life  fully  elaborated,  for  when  protein  is  absent 
from  the  food,  the  body  protein  is  utilized  to  maintain  the 
vital  functions,  even  if  nitrogen  compounds  of  a  lower  order 
are  present.  This  is  a  truth  of  great  significance  in  its 
relation  to  the  nutrition  of  man.  The  nitrogenous  tissues 
are  those  that  largely  determine  the  vigor  and  quality 
of  any  individual,  and  as  these  are  formed  rapidly  in 
the  early  stages  of  growth,  a  normal  and  unrestricted 
development  demands  an  adequate  supply  of  protein 
food. 

The  proteins  are  a  source  to  the  body  of  two  important 
ash  constituents,  viz.,  phosphorus  and  sulfur.  There  are 
reasons  for  believing  that  these  two  elements  enter  into 
the  building  of  the  protein  tissues  only  when  they  are 
supplied  in  the  food  in  their  protein  combinations.  It 
does  not  seem  to  be  definitely  proven  that  their  inorganic 
salts  may  be  used  by  the  animal  organism  for  synthesizing 
phosphorus  and  sulfur-bearing  proteins. 

159.  Relative  efficiency  of  different  proteins.  —  The 
relative  efficiency  of  protein  according  to  its  source  is  one 
of  importance.  Have  vegetable  proteins  as  large  con- 
structive value  as  those  of  animal  origin?  Is  a  larger  pro- 
portion of  the  proteins  of  milk  and  meat  available  for  the 
building  of  animal  tissue  than  when  derived  from  the 
cereal  grains?  We  have  seen  that  the  "  building  stones  " 
of  animal  proteins  differ  materially  in  proportion  from 
those  of  vegetable  proteins.  Abderhalden  l  calls  attention 
in  the  following  table  to  the  much  larger  proportion  of 
glutamic  acid  in  the  proteins  of  plant  origin  as  related  to 
their  value  for  constructive  purposes  :  — 

.  *  "  Phys.  Chemistry,"  1908,  p.  653,    See  Note,  p.  199. 


Efficiency  of  Proteins  153 


TABLE    XXII 

GLUTAMIC  ACID  IN  100  GRAMS  PROTEIN 

GRAMS 

Gliadin  (wheat) 37.17 

Gliadin  (rye) 33.81 

Hordein  (barley) .     .     .     .  36.35 

Zein  (maize) 16.87 

Glutenin 23.42 

Legumin 16.6 

-   Vignin  (peas) 16.89 

Conglutin  (lupine)       .     . '  :. ; 20.96 

Casein i     .     .r  . 10.7 

Egg  albumin 8.0 

Albumin  (fish  muscle) 8.9 

Albumin  (ox  muscle) 11.9 

Serum-albumin 7.7 

Serum-globulin " 8.5 

These  figures  indicate  that  flesh  foods  are  relatively  more 
economical  for  tissue  formation  than  vegetable  foods.  The 
proteins  of  flesh  foods  are  themselves  like  the  proteins 
that  must  be  built  into  the  animal  body,  and  it  seems 
plausible  that  their  building  stones  can  be  used  with  less 
waste  than  can  proteins  of  quite  unlike  constitution. 

Vori  Noorden,1  an  authority  of  note,  estimates  that  suck- 
lings are  able  to  convert  90  per  cent  of  food  protein  into 
body  protein,  but  suggests  that  the  proteins  of  milk  are 
particularly  well  adapted  to  reconstitution. 

The  same  author  also  suggests  on  theoretical  grounds 
that,  in  general,2  "  no  more  than  80  grams  of  body  protein 

1  "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  I,  p.  71. 

2  LOG.  cit.,  p.  70. 


154  Principles  of  Human  Nutrition 

could  be  formed  from  100  grams  of  protein  in  the  food." 
This  whole  question  must  for  the  present  be  considered  on 
a  theoretical  basis,  but,  at  the  same  time,  we  are  justified 
in  believing  that 1  "  a  given  quantity  of  protein  in  the  food 
cannot  yield  an  equal  amount  of  body  protein,  and  also 
that  animal  proteins  are  more  efficient  in  this  respect 
than  vegetable  proteins." 

160.  Protein  used  in  a  variety  of  ways.  —  The  functions 
of  the  proteins  are  not  restricted,  however,  to  the  use 
already  described.  According  to  existing  views,  they  are 
utilized  in  more  ways  than  any  other  class  of  nutrients. 
It  was  held  at  one  time  by  prominent  scientists  that  out- 
side the  vegetable  fats  the  proteins  are  the  sole  source 
of  animal  fats,  and  this  view  was,  not  so  very  long  ago, 
to  some  extent  accepted.  Indisputable  proof  to  the  con- 
trary is  now  in  our  possession,  and  some  investigators  even 
go  so  far  as  to  deny  the  possibility  of  the  formation  of  fat 
from  protein.  On  this  point,  opinion  is  divided.  Certainly 
we  must  be  convinced  that  nitrogen  compounds  of  the 
food  are,  with  some  species,  not  the  most  important 
source  of  animal  fat,  for  various  investigators,  such  as 
Lawes  and  Gilbert,  Soxhlet,  and  others,  have  shown 
upon  the  basis  of  searching  experiments  that  sometimes 
over  four-fifths  of  the  fat  stored  by  pigs  must  have  had  its 
origin  outside  the  food  protein  and  fat.  Besides  all  this, 
the  common  experience  of  feeders  of  animals  that  foods 
highly  non-nitrogenous  are  often  the  most  efficient  for 
fattening  purposes  is  good  evidence  that  fat  formation  is 
not  greatly  dependent  upon  the  protein  supply.  Never- 
theless, the  possibility  of  producing  animal  fat  from 

1  Loc.  cit.,  p.  69. 


Efficiency  of  Proteins  155 

protein  is  not  disproved,  and  there  are  several  considera- 
tions which  make  it  seem  probable  that  under  certain  con- 
ditions, this  does  occur. 

Protein  can  unquestionably  serve  as  fuel,  or,  in  other 
words,  as  a  source  of  energy.  (See  p.  162.)  The  amount 
so  used  depends  much  upon  the  subject  and  character  of 
the  ration.  In  the  case  of  mature  carnivorous  animals  and 
adult  persons  who  neither  gain  nor  lose  in  flesh,  the  pro- 
tein eaten  serves  as  a  source  of  energy  rather  than  of  con- 
structive material.  When  a  portion  of  the  protein  is 
required  for  milk  formation  or  for  building  tissue  in  the 
growing  body,  a  varying  quantity  escapes  oxidation. 

The  formation  in  the  animal  of  carbohydrates  from 
protein  appears  to  be  proven.  We  have  seen  that  the 
sugar  formed  during  digestion  may  be  stored  as  glycogen, 
and  that  this  glycogen  in  the  liver  and  muscles  is  a  re- 
serve store  of  fuel  to  maintain  the  activities  of  the  ani- 
mal body,  and  it  is  important  to  know  whether  the 
contribution  of  energy  from  the  digested  protein  is  through 
the  same  avenue.  There  are  now  good  grounds  for  be- 
lieving that  this  may  be  the  case. 

In  the  plant,  the  amino  acids  which  are  the  building 
stones  of  the  proteins  are  synthesized  from  the  carbohy- 
drates and  lower  nitrogen  compounds,  and  there  seems 
to  be  no  reason  why  a  reverse  process  may  not  take  place. 
Much  investigation  has  been  directed  at  this  problem  that 
did  not  furnish  a  conclusive  answer,  although  in  some 
experiments  the  sugar  formed  when  a  pure  protein  diet 
was  fed,  can  be  accounted  for  only  by  deciding  that  it  was 
due  to  protein  cleavage.  Nevertheless,  the  question  will 
bear  further  study. 


156  Principles  of  Human  Nutrition 

161.  Functions  of  carbohydrates.  —  Carbohydrates  are 
usually  characterized  as  the  fuel  portion  of  the  food,  or 
that  part  which  is  burned  to  produce  the  various  forms  of 
energy.     This  conception  of  the  function  of  these  bodies 
is  correct  in  the  sense  that  in  many  dietaries  they  con- 
stitute the  larger  part  of  the  fuel,  although  not  the  whole 
of  it,  and  in  some  dietaries  less  than  half.     For  instance, 
the  diet  of  a  certain  ball  team  contained  on  the  average 
daily  181  grams  of  protein,  557  grams  of  carbohydrates, 
and  292  grams  of  fat.     If  the  young  men  neither  lost  nor 
gained  in  flesh,  the  protein  of  their  diet  supplied  about 
one-eighth  of  the  fuel  energy  that  they  expended,  the 
remainder  coming  about  equally  from  the  carbohydrates 
and  fats. 

In  contrast  to  this,  Japanese  students  in  the  cadet  school 
at  Tokyo  were  found  to  eat  83  grams  of  protein,  631 
grams  of  carbohydrates,  and  14  grams  of  fat.  In  this 
case,  over  80  per  cent  of  the  fuel  energy  came  from  the 
carbohydrates.  As  we  shall  see  later  (pp.  161-162)  all 
the  nutrients  may  serve  as  fuel  in  the  body,  but  in 
the  dietaries  of  many  classes  of  people  the  carbohydrates 
are  the  chief  source  of  the  energy  that  comes  from  food 
oxidation. 

162.  Carbohydrates  a   source   of  animal    fats.  —  Con- 
trary to  views  that  held  for  a  time,  it  is  now  well  estab- 
lished that  the  animal  fats  may  have  their  source  in  the 
carbohydrates ;    in  other  words,   starch   and  sugar  and 
related  bodies  may  serve  the  main  purpose  in  producing 
body   fat.     In   many   experiments,    notably   those   with 
swine,  the  protein  and  fat  of  the  food  have  fallen  far  short 
of  accounting  for  the  fat  in  the  body  increase,  sometimes 


Food  as  Source  of  Energy  157 

much  the  greater  part  of  the  latter  having  no  possible 
source  other  than  the  carbohydrates.  A  practical  expres- 
sion of  this  general  conclusion  concerning  the  fat-forming 
function  of  carbohydrates  is  seen  in  the  well-recognized 
value  of  corn  meal  as  a  fattening  food,  a  feeding  stuff 
nearly  seven-tenths  of  which  consists  of  starch.  Recent 
experiments  with  milch  cows  leave  no  doubt  that  milk 
fat  may  also  be  derived  from  carbohydrates. 

163.  Functions  of  the  fats  and  oils.  —  So  far  as  is  at 
present  known,  the  possible  uses  of  the  food  fats  and  oils 
and  of  the  carbohydrates  are  similar.  In  other  words, 
both  may  serve  as  fuel,  and  both  may  be  a  source  of  animal 
fat.  The  differences  are  that  the  supply  of  carbohydrates 
is  much  the  larger,  and  the  fuel  value  of  a  unit  weight  of 
fat  much  the  greater.1  Moreover,  it  seems  possible  for  a 
vegetable  fat  to  become  deposited  in  the  animal  without 
essential  change,  whereas  fat  formation  from  carbohy- 
drates involves  complex  chemical  transformations. 

C.    FOOD  AS  A  SOURCE  OF  ENERGY 

The  fact  that  all  the  organic  compounds  of  the  food  may 
serve  as  a  source  of  energy,  and  as  the  larger  portion  of 
the  food  is  utilized  for  energy  purposes,  it  seems  wise  to 
give  this  phase  of  nutrition  a  somewhat  special  considera- 
tion. The  living  animal,  either  as  a  whole  or  in  some  of 
its  parts,  is  constantly  in  motion.  This_means^  that  the 
animal  mechanism  is  ceaselessly  performing  work.  Even 
if  the  body  is  apparently  quiet,  the  heart  beats,  pumping 
blood  to  all  parts  of  the  body,  the  lungs  are  expanded  and 
contracted,  and  the  stomach  and  intestines  keep  up  the 
movements  which  are  essential  to  digestion.  Besides,  a 


158  Principles  of  Human  Nutrition 

living  body  is  the  seat  of  continuous,  invisible,  and  complex 
chemical  and  physical  changes,  such  as  the  breaking  up  of 
compounds  in  digestion  and  their  rebuilding  in  assimila- 
tion, that,  if  not  work  in  the  common  meaning  of  the  term, 
are  its  equivalent.  Walking,  pulling,  lifting,  pumping 
blood,  breathing,  masticating,  digesting  and  assimilating 
food,  represent,  then,  a  great  variety  of  operations  of 
living  machines. 

Now  work  requires  the  expenditure  of  energy.  The 
projection  of  a  rifle  ball  through  space  at  the  rate  of  two 
thousand  feet  per  second  is  work.  The  ball  does  not 
move  of  itself,  but  is  propelled  by  the  application  of  the 
energy  stored  in  a  powerful  explosive.  Back  of  every 
one  of  our  great  mechanical  operations,  such  as  pumping, 
grinding,  and  moving  railroad  trains,  will  always  be  found 
some  sort  of  energy,  and  what  is  true  of  machinery  made 
of  wood  and  iron  is  equally  true  of  that  made  of  bone  and 
muscle.  The  fact  that  the  mechanism  is  alive  does  not 
abrogate  a  single  physical  law,  so  that  the  fundamental 
principles  of  energy  as  applied  to  machines  are  directly 
applicable  to  the  activities  of  animal  life. 

It  is  safe  to  go  farther,  and  say  that  the  animal  organism 
does  not  originate  energy.  Among  the  fundamental  con- 
ceptions upon  which  all  our  knowledge  of  chemical  and 
physical  laws  rests  is  this,  that  energy  and  matter  are 
indestructible,  and,  moreover,  that  the  sum  total  of  these 
in  the  universe  is  unchangeable.  If,  then,  man  expends 
the  muscular  energy  necessary  to  propel  a  bicycle  over 
one  hundred  miles  of  road,  the  equivalent  of  this  must 
have  been  supplied  to  his  body  from  some  outside 
source.  He  could  not  create  it.  We  know  that  this 


Forms  of  Energy  159 

is  so,  and  we  also  know  it  must  be  conveyed  to  him  in 
his  food. 

164.  Manifestations  of  energy.  —  In  considering  this 
subject  it  is  natural  to  first  ask,  what  is  energy?  This  is 
a  difficult  question  to  answer  in  a  popular  way,  and  the 
physicists'  definition  would  hardly  serve  our  purpose. 
All  we  can  do,  perhaps,  is  to  illustrate  it  by  pointing  out 
some  of  its  manifestations.  Let  us  resort  to  an  old  illus- 
tration. Every  farmer's  boy  has  doubtless  seen  a  black- 
smith hammer  an  iron  rod  until  it  was  red-hot.  The 
motion  of  the  hammer-head  descending  with  great  ve- 
locity was  suddenly  arrested  when  it  came  in  contact  with 
the  rod.  This  descent  of  the  hammer-head  illustrated 
one  form  of  active  energy,  viz.,  motion  of  a  mass  of  matter. 
When  the  hammer  met  the  iron  rod  on  the  anvil,  the 
mass  motion  ceased.  Was  the  energy  therefore  lost? 
Not  unless  our  fundamental  conception  is  wrong,  and  we 
find  that  in  this  case  it  is  not.  The  physicist  teaches  us 
that  the  energy  represented  by  the  moving  mass  of  matter, 
that  is,  the  hammer-head,  was  communicated  to  the  mole- 
cules of  the  iron  rod,  and  as  the  vibrations  of  the  molecule 
increased  in  rapidity,  the  rod  grew  hotter  and  hotter. 
Here  we  have  another  illustration  of  energy,  viz.,  the  mo- 
tion of  the  molecule  or  heat  into  which  the  energy  of  mass 
motion  has  been  transformed.  The  iron  rod  might  have 
been  heated  in  another  way, — by  plunging  it  into  burning 
charcoal,  and  here  the  heat  energy  would  come  from  the 
combustion  of  the  carbon.  Somehow,  when  it  is  deposited 
in  the  plant,  there  becomes  stored  in  this  carbon,  in  a  way 
about  which  we  can  only  theorize,  what  perhaps  we  may 
call  the  chemical  energy  of  the  atom,  which,  when 


160  Principles  of  Human  Nutrition 

combustion  occurs,  is  changed  into  heat  or  molecular 
motion. 

Perhaps  another  illustration  may  still  further  serve  our 
purpose.  A  small  dynamo  is  being  run  by  a  pair  of  horses 
working  in  a  tread  power  such  as  is  used  for  threshing 
grain.  The  horses  are  constantly  climbing  up  a  moving 
treadway  and  thereby  communicating  muscle  energy  to 
motion  of  machinery.  This  motion  is,  by  the  dynamo, 
converted  into  electricity,  which,  by  passing  through  the 
carbon  film  of  an  incandescent  lamp  and  there  meeting 
resistance,  is  in  part,  at  least,  transformed  into  heat. 
We  have  then,  in  a  chain,  muscular  vibration,  motion  of 
the  mass  (pulleys,  wheels,  etc.),  electricity  and  heat,  all 
active  energies  and  all  transferable  the  one  into  the  other. 
This  is  a  fairly  good  picture  of  what  goes  on  with  the  horse 
or  man,  externally  and  internally,  in  sustaining  life  and 
performing  labor.  From  these  phenomena  we  learn  that 
not  only  are  there  several  forms  of  energy,  but  that  one 
form  is  transferable  into  another. 

165.  Energy  stored  in  plant  substance. — Back  of  it 
all,  and  this  is  what  interests  us,  is  the  animal's  food.  As 
a  result  of  years  of  patient  investigation,  it  has  become 
known  that  through  the  combustion  of  the  carbon  com- 
pounds of  vegetable  and  animal  origin,  which  serve  as 
nutrients,  chemical  energy  may  be  transformed  into  those 
other  forms  that  are  manifested  in  the  activities  of  living 
beings.  When  we  ask  from  whence  comes  the  energy 
given  up  by  the  plant  compounds,  we  arrive  at  our  last 
stage  of  inquiry.  Here  we  enter  the  domain  of  plant 
life,  and  it  is  a  notable  triumph  of  the  human  intellect 
that  we  are  able  to  declare  with  certainty  that  the  ceaseless 


Energy  Unit  161 

and  multiple  activities  of  life  on  this  planet  are  sustained 
by  an  energy  which  comes  to  the  plant  in  the  sun's  rays 
through  almost  limitless  space. 

166.  Energy  unit.  —  It  is  obvious  that  if  the  internal 
and  external  work  performed   by  man  is  sustained  by 
the  food,  it  is  desirable  to  measure  the  energy  avail- 
able 'in  different   foods,  provided,  of    course,   that    they 
differ  in  this  respect,  as  we  know  they  do.     In  order  to 
measure  anything,  we  must  have  a  standard  or  unit  of 
measurement.     In  this  case,  it  cannot  be  a  unit  of  space 
or  of  mass ;   that  is,  we  cannot  declare  that  wheat  flour  con- 
tains so  many  cubic  feet  or  pounds  of  available  energy. 
Energy  has  neither  dimensions  nor  weight.     If  we  measure 
it  at  all,  it  must  be  by  units  of  temperature  or  of  work 
performed.     Units  of  this  kind  are  applied  to  the  measure- 
ment of  food  energy.     The  one  most  commonly  in  use  is 
the  calorie,  this  being  the  energy  which,  in  terms  of  heat, 
is  sufficient  to  raise  the  temperature  of  one  pound  of 
water  4°  F.     Expressed  in  terms  of  work,   the    calorie 
is   very  nearly  1.53  foot   tons,  or,  in  other  words,  it  is 
equivalent    to    the    work    involved    in    lifting    one   ton 
1.53  feet. 

167.  Energy    units    in    food    compounds.  —  The    total 
energy  or  heat  units  developed  in  the  combustion  of  human 
foods  is  determined  in  an  apparatus  called  a  calorimeter. 
The  latest  form  of  this  device  is  one  in  which  food  material 
is  burned  under  pressure  in  the  presence  of  pure  oxygen, 
and  the  heat  evolved  is  all  used  in  warming  a  known 
weight  of  water.     Data  are  thus  obtained  from  which  it 
is   possible   to   calculate    the   calories   in    the   particular 
material  burned.     The  energy  value  of  single  compounds, 


162 


Principles  of  Human  Nutrition 


such  as  albumin,  starch,  and  sugar,  may  also  be  found  in  the 
same  way,  as  has  been  done  in  a  large  number  of  instances. 
These  data  show  that  the  heat  resulting  from  the  com- 
bustion of  the  compounds  of  the  same  class  is  not  the  same 
in  all  cases.  The  value  in  calories  of  one  gram  (about 
one-twenty-eighth  of  an  ounce)  of  the  several  nutrients 
is  shown  in  the  following  table :  — 


TABLE    XXIII 
ENERGY  VALUES  OF  FOOD  COMPOUNDS 


Proteins 


Cal. 

Wheat  gluten     ....  5.99 

Gliadin 5.92 

Glutenin 5.88 

Plant  fibrin 5.94 

Serum-albumin       .     .     .  5.92 

Milk  casein 5.86 

Yolk  of  egg 5.84 

Carbohydrates 

Cal. 

Starch       . 4.18 

Cellulose  ......  4.18 

Glucose 3.74 

Cane  sugar    ...     .     .  3.95 

Milk  sugar 3.95 

Maltose    .:....  3.95 

Zylose       ......  3.74 


Cal. 

Egg  albumin     ....  5.73 

Muscle  (pure)  ....  5.72 

Blood  fibrin      5.64 

Peptone 5.30 

Wool     .......  5.51 

Gelatin 5.27 

Asparagin  (amide)     .     .  3.45 


Fats 


Cal. 


Of  swine 9.38 

Of  oxen   ......  9.38 

Of  sheep 9.41 

Maize  oil 9.28 

Olive  oil 9.47 

Ether  extract  of  oats      .  8.93 

Ether  extract  of  barley  .  9.07 


For  illustration,  the  energy  value  of  a  pound  of  edible 
material  from  a  few  foodstuffs  is  given  as  follows  :  — 


Available  Energy 


163 


Cal. 

.     .  1210 

.     .  1655 

.     .  310 

.     .  720 

..     .  325 

Butter     ......  3615 

Oysters   ......  260 


Sirloin  steak 
Corned  beef 
Fresh  codfish 
Eggs  .     .     . 
Milk  . 


Cal. 

Wheat  flour    ....  1645 

Oat  meal 1845 

Sugar 1820 

Molasses 1360 

Potatoes 375 

Squash  (canned)      .     .  250 

Apples 320 


These  figures  mean  that  when  a  pound  of  each  of  these 
foods  is  wholly  burned,  the  heat  produced  is  as  stated. 
It  has  been  demonstrated,  too,  by  severe  and  elaborate 
investigations  that  the  law  of  the  correlation  and  conser- 
vation of  energy  holds  in  the  animal  organism  as  it  does 
with  machinery,  or,  in  other  words,  the  energy  given  off 
as  animal  heat  has  been  measured  and  found  to  be  exactly 
equivalent  to  the  food  energy  minus  that  in  the  various 
excreta. 

168.  Available  energy.  —  We  must  distinguish,  how- 
ever, between  the  heat  produced  when  any  food  substance 
is  wholly  oxidized  in  a  calorimeter,  and  the  heat  or  energy 
which  is  available  when  the  same  material  is  applied  to 
physiological  uses.  It  never  happens  that  the  combustible 
portion  of  a  ration  is  entirely  burned  in  the  animal. 

In  the  first  place,  food  is  practically  never  all  digested, 
and,  as  only  the  digested  portion  furnishes  energy,  the 
available  fuel  value  of  a  ration  must  be  based  primarily, 
not  upon  the  total  quantity  of  dry  matter  it  represents, 
but  upon  the  amount  which  is  dissolved  and  passes  into 
the  blood.  If  all  foods  were  digested  in  the  same  propor- 
tion and  with  the  same  ease,  their  total  fuel  values  might 
show  their  relative  energy  worth,  but  as  digestion  coeffi- 


164  Principles  of  Human  Nutrition 

cients  for  the  various  food  materials  vary  greatly,  it  is 
evident  that  the  fuel  waste  in  the  feces  is  not  uniform. 

In  the  second  place,  the  digested  proteins  are  never 
fully  burned.  A  portion  of  these  compounds  always  passes 
off  in  the  urine  unoxidized,  the  fuel  value  of  which  is  lost 
to  the  animal.  For  this  reason,  the  available  energy  of 
the  digested  protein  is  about  one-fourth  less  than  the 
total. 

In  the  third  place,  there  is  an  escape  from  the  alimen- 
tary canal  of  unconsumed  gases,  due  to  the  fermentations 
which  take  place  during  the  latter  states  of  digestion. 
These  gases,  mostly  methane  (marsh  gas),  have  their 
source  mostly  in  the  carbohydrates.  With  farm  animals 
the  loss  of  energy  in  gases  has  been  found  to  vary  from  10 
to  20  per  cent  of  the  digested  dry  substance  of  the  food. 
With  the  human  species,  the  loss  is  much  less  and  is  per- 
haps almost  negligible. 

We  are  to  understand,  then,  that  the  available  energy 
of  food  is  represented  by  the  fuel  value  of  the  dry  matter 
which  is  digested  from  it,  minus  the  dry  matter  of  the 
urine  and  that  lost  in  gases. 

If,  however,  we  wish  to  know  the  actual  energy  gain 
from  a  particular  diet,  we  must  go  farther  than  a  deter- 
mination of  its  available  energy. 

169.  Net  energy.  —  Within  a  comparatively  short  time 
we  have  begun  to  speak  of  the  net  energy  of  foods,  and  as 
this  is  a  practical  consideration  which  is  likely  to  be  the 
subject  of  much  future  discussion,  it  is  well  to  notice  it  in 
an  explanatory  way.  As  we  have  learned,  food  is  not 
applied  to  use  until  it  reaches  the  blood.  Between  the 
time  when  it  is  taken  into  the  mouth  and  when  it  passes 


Net  Energy  165 

into  the  circulation,  it  must  have  work  expended  on  it  in 
the  way  of  mastication,  solution,  and  moving  it  along  the 
digestive  tract,  and  it  appears  highly  probable  that  the 
amount  of  this  work  per  pound  of  food  must  vary  greatly 
in  different  cases.  In  fact,  we  know  this  is  so  from  the 
result  vof  some  masterly  investigations  conducted  by 
Zuntz  in  Germany.  By  means  of  various  devices  and 
methods,  a  description  of  which  would  be  out  of  place 
here,  he  measured  the  oxygen  consumption  necessary  to 
sustain  the  mechanical  energy  of  mastication  and  diges- 
tion with  a  horse,  and  he  calculates  from  his  determina- 
tions that  the  following  heat  units  represented  the  energy 
used  in  chewing  certain  feeding  stuffs :  — 

*  CAL.  CAL. 


1  lb.  hay 76 

1  lb.  oats  21 


1  lb.  corn 6| 

Green  fodder  equal  to  1  lb. 
hay     ...  47 


The  differences  revealed  by  these  figures  are  interesting 
and  important.  Chewing  green  food  cost  in  labor  only 
about  62  per  cent  of  the  effort  required  to  masticate  its 
equivalent  of  dry  hay,  the  proportions  of  labor  for  hay, 
oats,  and  corn  being  in  the  ratio  of  100,  27,  and  8|. 

This  author  goes  farther  and  calculates  that  the  work 
of  mastication  and  digestion  combined  is  48  per  cent  of  the 
energy  value  of  the  digested  material  from  hay  and  19.7 
per  cent  of  that  from  oats.  To  be  sure,  these  results  were 
obtained  with  a  horse  and  do  not  apply  to  man,  but  they 
serve  to  illustrate  the  fact  that  the  mastication  and  diges- 
tion of  food  is  work  and  requires  an  expenditure  of  energy. 
The  fact  is  also  evident  that  the  expenditure  of  energy 


166  Principles  of  Human  Nutrition 

varies  with  the  mechanical  condition  of  the  foods,  though 
not  to  the  same  extent  perhaps.  All  these  deductions  are 
based  upon  the  excess  of  oxygen  used  when  the  work  of 
chewing  and  digestion  is  going  on  over  that  used  in  the 
absence  of  such  effort. 

If  we  wish  to  ascertain  the  comparative  energy  worth 
of  two  unlike  foods,  it  would  obviously  be  incorrect  to 
multiply  the  total  quantities  of  protein,  carbohydrates, 
and  fats  in  each,  by  the  unit  heat  values,  in  order  to  ascer- 
tain the  relative  energy  gain  to  the  animal  body. 

To  recapitulate,  we  may  define  available  energy  as  total 
energy  minus  that  which  is  lost  in  the  excreta  and  in  gases 
which  escape,  and  net  energy*  as  available  energy  minus  the 
cost  of  digestion  and  of  preparing  the  food  for  use.  Net 
energy  is  the  balance  of  profit  to  the  body. 

170.  Factors  used  in  computing  food  values.  —  It  is 
shown  on  pp.  161-162  that  the  different  food  compounds, 
even  of  the  same  class,  have  somewhat  different  heat  val- 
ues. These  are  total  values,  also,  and  make  no  allowance 
for  losses  in  the  urine  solids  and  in  digestion.  Riibner, 
basing  his  figures  on  experiments  with  dogs,  adopted  cer- 
tain factors  for  the  calorific  values  of  the  several  classes 
of  nutrients.  Sherman,1  in  a  very  recent  publication,  sug- 
gests somewhat  smaller  factors  as  more  nearly  represent- 
ing the  net  value  of  the  constituents  of  foods.  Both  sets 
of  factors  are  given  below. 

RUBNER  SHERMAN 

Protein 4.1  4.0 

Carbohydrates 4.1  4.0 

Fats    . 9.3  9.0 

1  "  Chemistry  of  Food  Nutrition,"  p.  125. 


Energy  Relations  of  Nutrients  167 

171.  Energy  relations   of  the   several    nutrients.  —  As 
has  been  pointed  out,  the  animal  body  is  the  field  of 
numerous  mechanical  activities  which  are  sustained  by 
the  energy  derived  from  the  food.     What  is  the  relation  of 
the  several  nutrients  to  these  manifestations  of  vital  energy 
is  an  interesting  and,  in  some  ways,  an  intensely  practical 
matter.     For  instance,  has  protein  a  peculiar  function  in 
the  maintenance   of  muscular   activity  which  no   other 
nutrients  have?     The  belief  prevailed  at  one  time  that 
muscular  contraction  caused  a  wasting  of  the  muscle  sub- 
stance which  must  be  replaced  by  the  protein  compounds 
of  the  food ;  in  other  words,  protein  alone  was  believed  to 
sustain  the  work  of  the  animal  body,  both  internal  and 
external.     It  would  follow  from  this  that  the  more  work  is 
done,  the  more  protein  is  needed.      This  view  is  no  longer 
held.     The  more  exact  methods  of  modern  research  have 
revealed  the  fact  that  an  increase  of  muscular  effort,  even 
up  to  a  severe  point,  increases  but  little,  if  any,  the  nitro- 
gen compounds  of  the  urine,  these  being  the  measure  of 
the  protein  that  is  destroyed.     There  has  come  to  light  a 
corresponding  fact  that  the  consumption  of  fuel  in  the 
body  other  than  proteins  increases  proportionately  with 
the  increase  of  work.     This  means  that  mechanical  work 
is  largely  sustained  through  the  combustion  of  carbohy- 
drates and  fats,  and  that  while,  for  reasons  we  do  not  yet 
wholly  understand,  a  fairly  generous  amount  of  protein 
seems  to  promote  the  well-being  of  the  laborer,  the  non- 
nitrogenous  nutrients    mostly  supply  the    extra  energy 
demanded  for  the  labor. 

172.  Heat  relations.  —  The  question  is  very  naturally 
asked,  as  no  energy  is  lost,  into  what  is  the  energy  of 


168  Principles  of  Human  Nutrition 

muscular  contraction  converted,  as,  for  instance,  that 
required  for  walking,  the  beating  of  the  heart  and  the 
work  of  the  intestines?  It  is  concluded  by  physiologists 
that  muscular  energy  used  by  the  living  organism  is  partly 
transformed  into  external  motion  and  partly  into  heat, 
and  this  certainly  is  consistent  with  facts  as  observed. 
Violent  exercise  by  the  animal  greatly  increases  the  pro- 
duction of  heat.  We  know  this  is  so,  because,  under  these 
conditions,  an  increased  amount  of  blood  is  thrown  to  the 
surface  of  the  body,  thereby  greatly  increasing  the  loss 
of  heat  by  radiation ;  perspiration  sets  in,  and  with  it  the 
consequent  evaporation  of  much  more  moisture,  thus 
disposing  of  much  heat.  Accurate  determinations 1  reveal 
an  increase  of  insensible  perspiration  (from  lungs  and  skin) 
from  an  average  of  960  grams  of  water  per  day  for  men  at 
rest,  to  an  average  of  4272  grams  for  men  at  work.  This 
shows  what  an  important  factor  is  the  evaporation  of 
water  from  the  body  in  heat  regulation.  The  dog,  and 
sometimes  other  animals,  pants  and  thereby  causes  a  large 
loss  of  heat  from  the  expanded  surface  of  the  moist  tongue. 
All  this  occurs  without  reducing  the  body  temperature 
below  the  normal.  In  fact,  nature  adopts  these  various 
devices,  such  as  increased  circulation  of  the  blood  and 
perspiration,  in  order  to  regulate  the  body  temperature 
and  prevent  its  rising  above  the  proper  point.  The  expla- 
nation of  this  greater  heat  during  labor  is  that  the  me- 
chanical energy  manifested  by  the  muscles  is  converted  to 
heat,  which,  under  circumstances  of  severe  exercise,  is  more 
than  enough  to  keep  the  body  at  its  usual  temperature  and 

1  "  Metabolism  and  Energy  Transformations  of  Healthy  Man  during 
Rest,"  Benedict  and  Carpenter,  p.  114. 


The  Critical  Temperature  169 

maintain  the  usual  radiation.  When  it  is  severely  cold, 
on  the  other  hand,  vigorous  exercise  is  sometimes  neces- 
sary in  order  to  keep  sufficiently  warm. 

The  view  is  now  held  that  all  body  heat  is  a  secondary 
product,  that  combustion  first  supports  muscular  activity 
with  heat  as  the  waste  product;  in  fact,  that,  under  the 
majority  of  conditions,  no  food  is  burned  primarily  to  keep 
the  animal  warm.  There  is  much  evidence  to  support 
this  position. 

173.  The  critical  temperature.  —  The  possible  combus- 
tion of  food  for  the  purpose  of  warming  the  animal  body 
should  not  be  denied,  however.  Recent  investigations 
indicate  that  under  given  conditions  there  is  an  air  tem- 
perature called  the  critical  temperature,  at  which  metab- 
olism (oxidation)  reaches  a  minimum.  If  the  air  tem- 
perature falls  below  this  point,  thus  causing  a  greater 
radiation  of  heat  from  the  body  surface,  increased  oxida- 
tion occurs.  If  the  temperature  rises  above  this  point, 
there  is  no  diminution  of  oxidation,  but  rather  a  slight 
increase;  hence  the  conclusion  that  there  is  a  minimum 
oxidation  necessary  to  the  maintenance  of  the  vital  func- 
tions which  must  go  on,  however  much  the  demands  for  the 
radiation  of  heat  may  be  lessened  by  a  rise  of  the  air 
temperature.  Down  to  a  certain  temperature  point,  the 
oxidation  necessary  for  maintaining  the  work  of  the  body 
gives  off  enough  heat  as  a  waste  product  to  keep  the  body 
temperature  up  to  98.6°  C.  Above  the  critical  temperature 
an  excess  of  heat  must  be  disposed  of.  What  this  critical 
temperature  is  for  man  does  not  appear  to  have  been  deter- 
mined. Whichever  way  the  air  temperature  moves  from 
the  critical  point,  there  is  heat  regulation,  this  being 


170  Principles  of  Human  Nutrition 

chemical  for  the  lower  temperature,  and  physical  for  the 
higher. 


\ 


D.  THE  NUTRITIVE  INTERRELATION  OF  THE  FOOD 
COMPOUNDS  AND  THE  NEED  OF  COMBINING  THESE 
IN  THE  DIET 

As  we  have  seen,  the  conclusion  reached  by  many  ex- 
tended and  severe  investigations  is  that  the  compounds  of 
foods  have  certain  functions  in  common.  For  instance, 
the  proteins,  carbohydrates,  and  fats  are  all  oxidized 
wholly  or  in  part  to  supply  the  necessary  energy  for 
muscular  activity.  The  proteins  then  serve  both  con- 
structive and  fuel  purposes.  Carbohydrates  and  fats  are 
alike  in  being  sources  of  energy  through  oxidation,  and  in 
being  utilized  for  the  deposition  of  animal  fat.  In  view 
of  these  facts,  the  question  arises  whether  the  physical 
welfare  of  the  human  subject  requires  the  mixture  of 
nutrients  that  commonly  exist  in  the  average  human  diet 
and  that  is  enforced  in  the  dietary  standards  that  are 
recommended  by  students  of  human  nutrition.  It  is 
certain  that  some  species  of  animals  may  exist  wholly  on 
a  flesh  diet  which  is  practically  devoid  of  carbohydrates. 
Even  man  himself,  in  the  wild  state  or  when  confined  to 
game  as  a  source  of  food,  is  able  to  subsist  for  a  consider- 
able period  of  time  on  animal  food  alone. 

174.  Carbohydrates  physiologically  economical.  —  Why 
do  food  standards  call  for  a  large  proportion  of  non- 
nitrogenous  material,  particularly  carbohydrates?  The 
necessity  of  protein  in  the  diet  is  abundantly  demonstrated. 
Many  investigations  have  shown  that  when  the  food 


Interrelation  of  Nutrients  171 

contains  no  protein,  the  waste  of  nitrogen  continues,  no 
matter  how  abundant  is  the  supply  of  carbohydrates  and 
fats.  In  other  words,  a  continuous  protein  cleavage  is 
demanded  by  the  animal  organism,  and  no  other  nutrients 
can  serve  as  a  substitute  for  protein  in  meeting  this 
demand.  If  the  food  contains  no  protein,  body  tissue  will 
be  depleted^  It  cannot  be  said  that  either  carbohydrates 
or  fats  are  an  essential  part  of  the  diet  in  the  sense  protein 
is,  because  it  is  possible  as  energy  producers  to  substitute 
one  for  the  other  and  protein  for  both. 

In  spite  of  these  facts,  it  is  safe  to  assert  that  the  welfare 
of  the  human  organism  is  best  promoted  by  a  food  carrying 
a  mixture  of  the  three  classes  of  nutrients.  The  larger 
part  of  man's  food  is  used  for  the  production  of  energy, 
and  it  is  physiologically  economical  that  this  energy  be 
supplied  by  the  non-nitrogenous  nutrients,  particularly 
carbohydrates.  If  the  proteins  are  broken  down  to  supply 
energy,  there  is  always  a  definite  proportion  of  urea  and 
uric  acid  residue  that  must  be  eliminated  through  the 
kidneys.  An  exclusive  protein  diet  would  burden  these 
organs  beyond  their  accustomed  habit,  and  flooding  the 
system  with  these  nitrogenous  wastes,  in  the  opinion  of 
medical  experts,  increases  the  tendency  to  gout  and  other 
forms  of  rheumatism.  On  the  other  hand,  the  carbohy- 
drates, when  not  stored  as  fat,  are  completely  oxidized  to 
the  simplest  compounds,  carbon  dioxid  and  water,  which 
are  eliminated  through  the  lungs  and  skin,  possibly  part  of 
the  water  so  formed  acting  as  a  solvent  of  the  urinary 
compounds.  Investigation  seems  to  prove  conclusively 
that  the  animal  body  has  a  physiological  preference  for 
carbohydrates  over  the  fats  or  other  nutrients  as  a  source 


172  Principles  of  Human  Nutrition 

of  energy.  After  the  free  ingestion  of  sugar  the  respira- 
tory quotient  in  certain  experiments  has  become  1.00  when 
just  previously  it  was  much  less  than  1.00.  This  demon- 
strates that  while  fat  was  being  oxidized  before  the  sugar 
was  taken,  the  oxidation  immediately  changed  wholly  to 
the  sugar.  This  indicates  the  physiological  adaptability 
of  starches  and  sugars  for  maintaining  muscular  activity. 
175.  Protein  sparers.  —  The  carbohydrates  and  fats 
are  sometimes  classed  as  "  protein  sparers."  This  means 
that,  with  an  adequate  supply  of  these  bodies  in  the  food, 
protein  destruction  may  be  reduced  to  the  lowest  possible 
limit.  To  illustrate,  if  a  man  doing  moderate  work  were 
maintaining  an  energy  balance  when  eating  of  digestible 
nutrients  218  grams  of  protein,  400  grams  of  carbohydrates, 
and  56  grams  of  fat,  and  100  grams  of  digestible  carbo- 
hydrates were  added  to  the  daily  food,  approximately 
100  grams  of  digestible  protein  could  undoubtedly  be 
withdrawn  from  the  daily  food  without  causing  any  drain 
upon  body  protein  to  meet  the  demands  of  the  organism. 
As  stated,  however,  such  a  substitution  cannot  be  carried 
beyond  certain  limits  without  depressing  the  protein  supply 
below  the  body  needs  for  maintenance.  Fats  are  not  as 
efficient  protein  sparers  as  are  carbohydrates.  To  be 
more  explicit,  fats  and  carbohydrates  do  not  replace  protein 
in  proportion  to  their  energy  equivalents,  carbohydrates 
being  the  more  efficient.  In  brief,  then,  experience  and 
science  both  indicate  that  carbohydrates  are  the  most 
healthful,  and  physiologically  the  most  economical, 
source  of  a  large  proportion  of  the  food  energy  used  by  the 
human  subject.  There  is  every  justification  for  the  rela- 
tive abundance  of  starch  foods  in  man's  diet. 


CHAPTER  VIII 
LAWS  OF  NUTRITION 

THE  preceding  pages  have  been  devoted  to  a  discussion 
of  the  origin  of  human  foods  :  what  they  are  in  substance, 
how  their  nutrients  are  made  available,  and  how  used. 
So  far  no  attempt  has  been  made  to  summarize  into  a 
systematic  statement  what  may  be  called  the  funda- 
mental principles  or  laws  of  nutrition,  some  of  which  we 
have  not  yet  directly  formulated,  but  which  are  inferences 
from  the  facts  presented.  It  is  desirable  to  do  this,  how- 
ever, before  passing  to  the  consideration  of  the  practical 
side  of  human  nutrition. 

176.  Food  source  of  all   energy  and  building  material. 
—  All  energy  and  building  material  applied  to  the  main- 
tenance and  growth  of  the  human  body  come  from  the 
food,  water  and  oxygen  being  included  in  this  term.     The 
human  organism  originates  neither  matter  nor  force. 

177.  Only   digested   food    available.  —  Only  that  por- 
tion of  the  food  which  is  digested,  i.e.,  that  which  is  dis- 
solved by  the  digestive  fluids  and  rendered  soluble  and 
diffusible  so  that  it  passes  into  the  blood,  is  available  for 
any  use  whatever.     This  fact  is  especialty  important  in 
view  of  the  greatly  varying  digestibility  of  different  foods. 

178.  Avenues    of    excretion.  —  The     undigested    food 
and  the  wastes  from  the  digested  food  pass  from  the  body 

173 


174  Principles  of  Human  Nutrition 

in  some  direction.  The  undigested  part  appears  in  the 
solid  excrement  or  feces.  The  urea  and  other  nitrogenous 
compounds  which  are  the  unoxidized  portion  of  the 
digested  protein,  pass  out  wholly  in  the  urine.  All 
digested  nitrogen  not  stored  is  found  here.  The  carbon 
dioxid  is  eliminated  through  the  skin  and  lungs,  chiefly 
the  latter,  and  water  is  disposed  of  through  the  kidneys, 
skin,  and  lungs. 

179.  Uses  of  digested  food.  —  The  digested  food  is  used 
in  two  general  directions  :  (a)  for  the  production  of  energy, 
and  (6)  for  constructive  purposes,  (a)  The  food  energy 
is  made  available  through  combustion,  i.e.,  the  oxidation 
of  the  carbon  compounds  of  the  food  to  simpler  substances, 
carbon  dioxid  and  water,  thus  liberating  the  energy  stored 
in  the  plant  during  its  growth.  Protein  is  never  fully 
oxidized,  but  carbohydrates  and  fats  may  be.  All  the 
organic  nutrients  may  be  oxidized  to  produce  energy,  the 
available  heat  values  of  protein,  carbohydrates,  and  fats 
being  approximately  as  1,  1,  2.25.  This  liberated  energy 
finds  expression  in  the  animal  organism  in  various  ways, 
as  heat,  mechanical  energy  or  motion,  and  chemical 
transformations.  The  total  energy  of  food  is  never  all 
available  for  use  because  of  a  loss  in  the  excreta  and  gases. 
Moreover,  the  net  energy  gain  seems  not  to  be  proportional 
to  the  available  energy,  but  is  dependent  upon  the  work  of 
digestion,  which  varies  somewhat  with  different  foods. 

(6)  The  food  compounds  are  used  for  constructive  pur- 
poses, either  without  changing  their  general  character, 
as,  for  instance,  the  building  of  muscular  tissue  from  the 
plant  proteins,  or  they  may  be  reorganized  into  bodies  of 
a  very  different  character,  as  in  the  formation  of  animal 


Laws  of  Nutrition  175 

fats  from  starch  and  sugar.  The  proteins  are  used  to 
construct  muscular  tissue;  in  fact,  all  the  nitrogenous 
parts  of  the  human  body,  and  they  are  perhaps  a  source 
of  fat.  Carbohydrates  can  only  be  used  constructively 
for  the  formation  of  fat,  and  the  same  is  true  of  food  fats 
or  oils.  Mineral  matter  is  needed  for  the  formation  of 
bone, -is  distributed  through  the  soft  tissues,  and  has  im- 
portant functions  in  digestion. 

180.  Food  balance.  —  The  matter  of  the  digested  food, 
including  water  and  oxygen,  is  exactly  equal  to  that  stored 
in  the  body  or  in  milk,  or  both,  plus  that  in  waste  prod- 
ucts, —  feces,  water,  carbonic  acid,  and  urine  solids.     Such 
a  balance  may  not  be  maintained  for  any  particular  day, 
but  will  ultimately  be  found  to  exist. 

181.  Food  requirements   definite.  —  Under  given  con- 
ditions of  species,  sex,  age,  climate,  and  use,  a  definite 
amount  of  digested  organic  matter  is  necessary  to  main- 
tain a  particular  person  without  gain  or  loss  of  body  sub- 
stance. ,  This  means  simply  that  tissue  wastes  must  be 
replaced,  and  the  fuel  supply  must  be  kept  up. 

If  an  individual  receives  no  food,  or  less  than  the  amount 
needed  for  maintenance  purposes,  tissue  waste  and  the 
production  of  energy  do  not  cease,  but  go  on  wholly  or  in 
part  at  the  expense  of  the  body  substance,  and,  as  it  is 
commonly  expressed,  the  person  "  grows  thin." 

182.  Production.  —  Food    supplied     above    a    needed 
maintenance  quantity  may  be  utilized  for  the  production 
of  new  substances  or  work.     In  the  proper  sense  of  the 
term,  no  production  ever  occurs  without  an  excess  of  food 
above    the    maintenance    requirement.     Milk    formation 
may  sometimes  go  on  at  the  expense  of  the  body  substance, 


176  Principles  of  Human  Nutrition 

but  with  proper  feeding,  milk,  flesh  or  muscular  work  are 
produced  at  the  expense  of  food  supplied  in  excess  of  that 
needed  for  maintenance. 

183.  Specific  requirements.  —  Regard  must  be  had  to 
the  supply  of  particular  nutrients  as  well  as  of  total  food. 
Even  with  a  person  doing  no  work  a  certain  amount  of 
protein  will  be  broken  up  constantly  into  urea  and  similar 
compounds,  an  amount  which  will  be  withdrawn  from  the 
body  tissues  to  the  extent  that  it  is  not  supplied  by  the 
food.     In  addition  to  this,  nursing  mothers,  for  instance, 
must  have  protein  for  the  formation  of  the  nitrogen  com- 
pounds of  milk,  or  a  growing  child,  for  the  growth  of  bone 
and  flesh  in  a  quantity  proportional  to  the  production,  and 
food  must  supply  it.     There  is,  therefore,  a  minimum  sup- 
ply of  protein,  which,  in  a  particular  case,  is  necessary  for 
maintenance   and   for   constructive   purposes,   less   than 
which  ultimately  diminishes  production  to  the  extent  of 
the  deficiency,  or  else  requires  the  use  of  body  tissue. 

184.  Nutrients  interchangeable  in  part.  —  The  different 
classes  of  nutrients  are  to  some  extent  interchangeable  in 
their  functions.     That  is  to  say,  all  the  organic  nutrients 
may  be  burned  to  supply  energy.     Protein  may  be  so 
used,  even  to  withdrawing  it  from  the  purposes  to  which 
it  is  necessary,  unless  the  carbohydrates  or  fats  are  sufficient 
to  protect  it  from  being  consumed  as  fuel.     A  proper 
supply  of  the  non-nitrogenous  nutrients  is  required,  there- 
fore, to  insure  the  application  of  the  necessary  minimum 
of  food  protein  to  its  peculiar  uses.     Carbohydrates  seem 
to  have  a  special  physiological  adaptation  to  energy  pro- 
duction. 


PART   II 

PKACTICAL  DIETETICS 


CHAPTER   IX 
GENERAL   CONSIDERATIONS 

THE  ultimate  aim  of  scientific  knowledge  relating  to 
human  nutrition  should  be  to  promote  the  healthful  and 
economical  use  of  food.  Unless  this  knowledge  has  a 
practical  application,  it  serves  merely  as  an  object  of  in- 
tellectual interest.  A  person  may  determine  what  he  shall 
eat  from  two  points  of  view,  viz.,  he  may  select  his  food 
on  the  basis  of  rational  considerations  of  health  and 
economy,  or  he  may  sensuously  follow  the  dictates  of  appe- 
tite. It  is  to  be  feared  that  the  latter  point  of  view  largely 
prevails.  Man  does  not  seem  to  regulate  his  diet  wisely 
by  an  intuitive  sense  of  what  is  best  for  his  physical  wel- 
fare, but  in  a  large  number  of  cases  is  the  unfortunate 
victim  of  unbridled  indulgence  in  that  which  most  delights 
his  taste,  but  eventually  ruins  his  health.  If  reason  dom- 
inates, then  many  questions  come  to  the  front,  some  of 
which  are  the  following :  — 

1.  The  amounts  and  proportions  of  the  various  foods 
that  best  meet  the  physiological  requirements  of  different 
classes  of  persons  in  their  varying  conditions-  of  age,  ac- 
tivity, and  environment. 

2.  The  selection  of  food  materials  that,  will  supply  a 
diet  physiologically  adequate  and  efficient  for  a  given  pur- 
pose. 

3.  The  economical  purchase  of  a  food  supply. 

179 


180  Principles  of  Human  Nutrition 

4.  Methods  of  preparing  foods  to  secure  dietetic  efficiency 
and  the  minimum  waste. 

5.  The  preservation  of  food. 

6.  Food  sanitation. 

Our  physiological  food  requirements  and  the  influence  of 
various  conditions  of  age,  activity,  and  environment  upon 
these  requirements,  as  shown  by  eating  habits. 

It  is  hoped  that  in  the  preceding  pages  it  has  been  made 
clear  that  through  the  matter  and  energy  supplied  in  food 
the  human  body  is  constructed  and  its  activities  maintained. 
It  should  also  be  plain  that  as  the  different  food  compounds 
have  unlike  functions,  all  of  these  must  be  found  in  a  diet 
that  will  build  and  sustain  a  normal  human  body.  We 
cannot  avoid  the  conclusion  either,  that  as  food  supplies 
the  raw  material  for  the  growth  of  body  tissue  as  well  as 
the  fuel  used  to  maintain  the  work  performed  by  the  human 
machine  both  internally  and  externally,  food  consump- 
tion must  necessarily  vary  greatly  with  different  indi- 
viduals. 

A.   How  STANDARD  DIETARIES  HAVE  BEEN 
ESTABLISHED 

Food  requirements  —  in  other  words,  dietaries  —  have 
been  the  subject  of  a  large  amount  of  study.  Several 
methods  of  inquiry  have  been  used,  perhaps  the  most  com- 
mon one  being  to  determine  what  amounts  of  nutrients  are 
actually  being  consumed  by  individuals  or  groups  of  indi- 
viduals living  under  various  conditions  of  age,  environment, 
and  activity.  In  this  way  there  has  been  studied  the  food 
consumption  of  children,  the  two  sexes,  professional  men 


Standard  Dietaries  181 

and  women,  persons  engaging  in  labor  of  unlike  severity 
and  persons  living  under  varying  environments  or  engaged 
in  special  occupations. 

185.  Method    of    study.  —  The   general   procedure   in 
these  studies  has  been  to  weigh,  and,  as  far  as  possible, 
analyze,  the  food  materials  purchased  for  the  individual 
or  group  of  individuals,  and  weigh  and  analyze  all  the  un- 
consumed   materials.     The   difference  between  the  pur- 
chased  food   and   that   unconsumed   represents  what  is 
actually  eaten.     In  many  cases,  as  for,  instance,  with  meats 
bought  in  large  bulk,  the  purchased  materials  have  been 
assumed  to  have  an  average  composition.     In  this  manner 
a  widespread  study  has  been  made  of  the  dietaries  of  differ- 
ent classes  of  people  in  the  United  States  where  habit, 
inclination,  the  limitation  of  means,  and  a  local  food  supply 
have  had  their  full  and  unrestrained  influence.     Similar 
studies  have  been  carried  on  in  an  extensive  way  by 
European  investigators. 

186.  Standard  dietaries.  —  Based  upon  the  results  of 
these   observations,    with   possibly   certain  modifications 
indicated  by  general  principles,   the  following  so-called 
standard  dietaries  have  been  suggested  which  are  given 
in  terms  of  protein,  carbohydrates,  and  fats,  together  with 
the  aggregate  energy  of  the  nutrients  in  each  dietary. 
The  dietaries  in  Tables  XXIV  and  XXV  are  a  statement 
of  food  consumption,  and  not  of  the  amounts  of  the  nutri- 
ents digested. 

In  the  table  l  immediately  following  may  be  found  the 
standards  suggested  some  years  ago  by  European  in- 
vestigators :  — 

1  "Chemistry  and  Economy  of  Food,"  Bui.  21,  O.E.S.,  p.  210. 


182 


Principles  of  Human  Nutrition 


TABLE  XXIV 

EUROPEAN  STANDARDS  FOR  DAILY   DIETARIES  FOR  PEOPLE  OF 
DIFFERENT  CLASSES 


NUTRIENTS 

POTEN- 
TIAL 

ENERGY 

Protein 

Fats 

Carbo- 
hydrates 

Total 

Children  : 

Grams 

Grams 

Grams 

Grams 

Calories 

1  to  2  years,  average  .... 

28 

37 

75 

140 

765 

2  to  6  years,  average  .... 

55 

40 

200 

295 

1420 

6  to  15  years,  average      .     .     . 

75 

43 

325 

443 

2040 

Aged  woman     
Aged  man 

80 
100 
92 

50 
68 
44 

260 
350 
400 

390 
518 
536 

1860 
2475 
2425 

Woman  at  moderate  work  . 

Man  at  moderate  work  (Voit) 

118 

56 

500 

674 

3055 

Man  at  hard  work  (Voit)    .     .     . 

145 

100 

450 

695 

3370 

Man   at   moderate   work    (Mole- 

schott)       

130 

40 

550 

720 

3160 

Man  at  moderate  work  (Wolff)    . 

125 

35 

540 

700 

3030 

Subsistence  diet  (Playfair)       .     . 

57 

14 

341 

412 

1760 

Diet  in  quietude  (Playfair)      .     . 

71 

28 

341 

440 

1950 

Adult  in  full  health  (Playfair)       . 

119 

51 

531 

701 

3140 

Active  laborers  (Playfair)    .     .     . 

156 

71 

568 

795 

3630 

Hard-worked  laborers  (Playfair)  . 

185 

71 

568 

824 

3750 

Dr.  W.  O.  Atwater,1  after  an  extensive  study  of  dietary 
conditions  in  the  United  States,  suggested  the  following 
for  the  conditions  prevailing  here,  which  may  be  regarded 
as  a  compromise  with  the  European  standards :  — 


1  Loc.  cit.,  p.  213. 


Standard  Dietaries 


183 


TABLE  XXV 
STANDARDS  FOR  DAILY  DIETARIES  (AMERICAN) 


PRO- 
TEIN 

FUEL 
VALUE 

NUTRI- 
TIVE 
RATIO 

1 

Grams 

Calories 

1: 

Woman  with  light,  muscular  exercise 

9 

90 

2400 

5.5 

Woman  with  moderate  muscular  work    . 
Man  without  muscular  work      .... 

1 

100 

2700 

5.6 

Man  with  light  muscular  work 

112 

3000 

5.5 

Man  with  moderate  muscular  work    .     . 

. 

125 

3500 

5.8 

Man  with  hard  muscular  work       .   "Y    . 

> 

150 

4500 

6.3 

It  is  to  be  observed  that  Dr.  Atwater's  standards  are 
rather  more  generous  than  the  European.  This  is  to  be 
expected  in  standards  based  upon  eating  habits,  for  the 
relatively  larger  supply  of  food  materials  in  the  United 
States  and  the  higher  wage  of  our  laboring  classes  con- 
duces to  more  generous  and  more  expensive  eating  habits. 

It  is  to  be  noted  that  these  tables  differ  in  the  terms 
in  which  the  standards  are  stated.  The  earlier  stand- 
ards are  given  in  terms  of  total  nutrients  in  the  food 
eaten.  Later  only  total  protein  and  the  energy  of 
the  total  food  are  stated,  while  Dr.  Langworthy  gives 
the  standards  in  terms  of  digestible  protein  and  utilizable 
energy. 

An  excellent  and  quite  complete  summary  of  the  results 
of  dietary  studies  throughout  the  world  has  been  presented 
by  Dr.  Langworthy.1 

1  Year  Book,  U.  S.  Dept.  Agr.,  1907,  p.  366. 


184 


Principles  of  Human  Nutrition 


TABLE  XXVI 

RESULTS  OF  DIETARY  STUDIES  IN  THE  UNITED  STATES  AND 
OTHER  COUNTRIES 


PERSONS 

TOTAL 
PRO- 
TEIN 
EATEN 

ENERGY 

OF 

TOTAL 
DIET 

DI- 
GESTED 
PRO- 
TEIN 

EN- 
ERGY 
UTIL- 
IZED 

United  States  : 

Grams 

Calories 

Grams 

Calo- 
ries 

Men  at  hard  muscular  work:    Artisans,  la- 

borers, etc.,  average  of  24  studied         .     . 

177 

6485 

162 

6000 

Athletes,  average  of  19  studies        .... 

198 

4980 

182 

4510 

Men  at  moderate  muscular  work  :    Farmers, 

artisans,    laborers,    etc.,    average   of    162 

studies    '. 

100 

3685 

92 

3425 

Men  not  employed  at  muscular  occupations: 

Business  men,  students,  etc.,  average   of 
51  studies    

106 

3560 

98 

3285 

•Men  with  little  or  no  muscular  work  :  Inmates 

of  institutions,  average  of  49  studies    .     . 

86 

2820 

80 

2600 

Very  poor  working  people,  average  of  15  studies 

69 

2275 

64 

2100 

Canada  :   Factory  hands,  average  of  13  studies  . 

108 

3735 

99 

3480 

West  Indies  : 

Farmers,  light  work,  Leeward  Islands    .     .     . 

82 



75 

3085 

Ireland  :   Workingmen    
England  :   Workingmen        

98 
89 



90 
82 

3107 

2685 

Scotland  : 
Workingmen 

108 

99 

3228 

Students    .          

143 

132 

3979 

Finland  : 

Workingmen       

Workingmen  (hard  work) 

114 
167 



105 
150 

3011 
4378 

Students         

157 

144 

3984 

Sweden  : 
"Workingmen 

134 

123 

3281 

Workingmen  (hard  work)     

189 

174 

4557 

Students   

127 



117 

3032 

Standard  Dietaries 


185 


TABLE  XXVI  —  Continued 

RESULTS  OP  DIETARY  STUDIES  IN  THE  UNITED  STATES  AND 
OTHER  COUNTRIES  —  Continued 


PERSONS 


TOTAL 
PRO- 
TEIN 

EATEN 


ENERGY 

OF 

TOTAL 
DIET 


DI- 
GESTED 
PRO- 
TEIN 


EN- 
ERGY 
UTIL- 
IZED 


Grama 
Russia : 

Factory  hands 119 

Miners  (hard  work) 155 

Northern  Italy :   Laborers 125 

Southern  Italy:   Laborers 148 

Italy :   Farmers  and  mechanics 125 

Germany : 

Workingmen  (hard  work) 134 

Farmers 137 

Professional  men Ill 

France : 

Men  (light  work) 110 

Farmers  (south  of  France) 149 

Belgium : 

Workingmen 92 

Farmers 136 

Poland:   Well-to-do  families 121 

Japan : 

Laborers 118 

Laborers  (hard  work) 158 

Professional  and  business  men 87 

Students 98 

Java :   Men  (light  work) 73 

China,  Lao-Kay :   Laborers 91 

Anam :   Laborers 134 

Egypt:   Native  laborers 112 

Congo:   Native  laborers 108 


Calories 


Grams 

109 
143 
115 
136 
115 

123 
126 
102 

101 
137 

84 
125 
111 

103 

137 

75 

88 

67 

83 

123 

103 

90 


Calo- 
ries 


3194 
4000 
3655 
4400 
3400 

3061 
4530 
2511 

2750 
4570 

3000 
4370 
3015 

4415 
5050 
2190 
2800 
2500 
3400 
3866 
2825 
2812 


186  Principles  of  Human  Nutrition 

187.  Influence  of  conditions.  —  A  study  of  the  fore- 
going tables  reveals  facts  of  importance,  principally  two : 
(1)  that  age  and  occupation  have  a  very  marked  influence 
'upon  actual  food  consumption,  and  (2)  that  food  con- 
sumption in  different  countries  under  unlike  physical  and 
economic  conditions  differs  greatly  even  with  persons 
of  the  same  class  and  kind  of  occupation.  The  first  fact 
is  in  accordance  with  the  bio-chemical  facts  we  have  been 
considering.  If  the  food  must  supply  the  energy  used  in 
internal  and  external  work,  then  the  more  units  of  work 
are  performed,  the  more  food  is  required.  The  child  is 
growing  rapidly  and  requires  building  material  which  the 
adult  does  not.  The  second  fact  of  the  unlike  consump- 
tion of  food  in  different  lands,  for  instance,  students  or 
men  at  hard  work,  is  related  in  part  to  certain  economic 
conditions  such  as  food  supply  and  wages,  but  at  the  same 
time  it  opens  a  question  of  large  import  which  will  be  quite 
fully  considered  later. 


B.  ACTUAL  FOOD  CONSUMPTION  AS  A  BASIS  FOR 
STANDARD  DIETARIES 

In  view  of  the  evident  variations  in  the  amount  of  food 
consumed  by  different  persons,  even  those  of  the  same  class, 
the  question  is  very  properly  raised  whether  the  measure- 
ment of  what  persons  of  various  classes  actually  eat  gives 
a  proper  basis  for  establishing  food  standards.  It  is 
popularly  asserted  that  most  persons  eat  too  much,  and 
that  less  food  would  conduce  to  better  health  and  ade- 
quately sustain  the  fullest  activities.  This  claim  is  also 
made  by  scientists  of  established  reputation,  and  carefully 


Necessary  Food  Consumption  187 

considered  evidence  is  presented  to  support  it.  It  must 
be  confessed  that  the  aim  of  scientific  investigation  should 
be  to  find  out  what  are  the  real  physiological  requirements 
of  persons  in  the  several  conditions  and  occupations  of  life, 
and  it  is  not  safe  to  assume  that  the  eating  habits  of  those 
individuals  selected  for  observation  are  necessarily  correct. 
We  know  it  to  be  true  that  many  persons  have  acquired 
luxurious  table  habits  even  to  gluttony,  and  we  are  sure  that 
much  disease  and  suffering  are  due  to  excessive  or  ill- 
advised  eating.  It  is  not  so  evident,  however,  that  the 
great  mass  of  persons  in  mediocre  circumstances  and  of 
sober,  well-ordered  lives  could  eat  much  less  to  the  physical 
advantage  of  themselves  and  the  race.  In  discussing  this 
question,  facts  both  of  .general  observation  and  those  de- 
rived from  scientific  inquiry  should  be  considered. 

188.  The  test  of  experience.  —  In  the  first  place,  it  must 
be  conceded  that  in  many  cases  where  unrestrained  food 
selection  and  consumption  have  prevailed,  generation 
after  generation  of  men  and  women  have  grown  to  a  nor- 
mal, well-developed,  and  healthy  type.  We  have  no 
reason  for  supposing  that  among  those  people  who  have 
shown  a  persistence  of  type  and  vigor  there  has  not  been 
a  free  satisfaction  of  appetite,  or,  conversely,  that  there  has 
been  either  a  voluntary  or  an  involuntary  limitation  of 
food  to  a  minimum.  Moreover,  an  excess  of  food  over  and 
above  real  physiological  needs  must  certainly  be  a  physi- 
ological burden,  and  jf  excessive  eating  is  generally  in- 
dulged in,  we  could  hardly  expect  such  instances  of  ap- 
parently perfect  health  and  great  vigor  in  persons  who 
freely  indulge  in  a  generous  diet.  It  should  be  admitted 
that  these  arguments  are  of  a  popular  character  and  are 


188  Principles  of  Human  Nutrition 

not  scientific  proof.     Let  us  turn  for  a  moment  to  argu- 
ments of  similar  nature  on  the  other  side. 

189.  Variable    individual    demands.  —  The    advocates 
\of  a  restricted  diet  point  to  the  greatly  variable  food  con- 
sumption by  different  individuals  of  apparently  healthy 
and  normal  life  as  good  evidence  that  some  must  certainly 
eat  more  than  they  need.     It  has  been  conceded  that 
[there  is  much  overeating,  which  is  the  cause  of  many 
physical  ills.     On  the  other  h'and  unlike  eating    is  not 
evidence  of  overeating  on  the  part  of  some  individuals. 
The  activities  of  the  human  organism  internal  and  exter- 
nal are  very  complex  and  are  greatly  unlike  with  different 
persons  without  the  fact  being  apparent.     One  person 
sits  quietly,  walks  with  the  least  effort,  and  uses  the  mini- 
mum effort  in  performing  a  given  amount  of  work,  while 
another  is  of  a  restless,  nervous  temperament,  is  constantly 
moving,  and  uses  unnecessary  exertion  in  accomplishing 
a  physical  task.     When  we  remember   that  all   physical 
activity  of  whatever  kind  is  sustained  by  an  exact  equiva- 
lent of  food  energy,  it  is  easy  to  understand  why  the  real 
food  needs  of  different  individuals  may  vary  greatly  be- 
cause of  unrecognized  differences  in  muscular  activity. 

190.  Fate  of   excess  food.  —  Again,   if  a  person  con- 
sumes carbohydrates  and  fat  in  excess  of  the  maintenance 
needs  of  the  body,  what  is  their  fate?     The  scientific  evi- 

|  dence  is  that  there  is  no  increase  in  energy  exchange ;  that 
is,  in  the  final  transference  of  the  potential  energy  of  the 

\food  into  heat,  which  is  the  measure  of  such  exchange, 
t>ut  that  the  surplus  is  stored  in  the  body.  It  is  hardly 
conceivable,  anyway,  that  the  energy  of  excess  food  would 
be  exactly  disposed  of  in  the  work  of  getting  rid  of  the  excess. 


Necessary  Food  Consumption  189 

If  this  were  the  case,  then  the  necessary  energy  expenditure 
would  be  directly  proportional  to  the  amount  of  food 
digested,  unless  storage  in  the  body  occurs,  —  an  absurd 
proportion. 

191.  Experimental  evidence.  —  Those  who  argue  for 
a  restriction  of  the  diet  below  the  ordinary  eating  practices 
point  to  certain  experimental  observations  as  furnishing 
proof  of  the  correctness  of  their  position.  Reference  is 
not  here  made  to  the  claims  of  food  "  faddists  "  who, 
without  any  adequate  knowledge  of  scientific  fundamentals 
and  without  accurate  observations,  proclaim  the  blessings 
of  a  minimum  diet.  Their  unsustained  assertions  may 
be  passed  by  without  discussion,  for  so  far  as  they  have 
been  investigated  they  have  proved  unreliable. 

When,  however,  such  a  distinguished  scientist  as  Dr. 
Chittenden  of  Yale  University  advocates  greater  modera- 
tion in  eating  and  presents  a  mass  of  carefully  observed 
data  to  sustain  his  views,  the  matter  becomes  worthy  of 
careful  consideration.  The  work  of  Chittenden l  was 
undertaken  primarily  to  investigate  the  minimal  necessary 
supply  of  protein,  but  the  data  permit  observations  on  the 
energy  supply.  It  seems  that  he  succeeded  in  maintaining 
a  uniform  body  weight  on  what  he  estimated  to  be  a  food 
energy  of  approximately  1600  calories  daily.  Under  the 
change  in  diet  his  weight  fell  from  144  pounds  to  about 
126.5  pounds,  after  what  it  remained  practically  constant. 
Observations  were  made  by  Dr.  Chittenden  on  four  other 
subjects  who  maintained  a  fairly  uniform  body  weight  on 
food  estimated  to  furnish  daily  from  2000  to  2500  calories. 
These  figures  seem  low  when  it  is  recalled  that  calorimeter 

1  "  Physiological  Economy  in  Nutrition,"  pp.  19-51. 


190  Principles  of  Human  Nutrition 

measurements  of  energy  exchange  by  several  subjects 
of  varying  weight  (43  to  82  kg.),  in  absolute  muscular  rest 
and  in  a  hunger  condition,  showed  a  daily  heat  production 
of  1214  to  1656  calories,  while  the  exchange  of  somewhat 
heavier  persons  when  asleep  has  been  found  to  vary  be- 
tween 1418  and  1853  calories.1  (See  Table  XXVII.) 

Chittenden's  five  subjects,  though  active,  were  engaged 
in  mental  rather  than  physical  labor,  and  were  of  light 
weight,  from  126  to  143  pounds  (57.3  to  65  kg.)  It  has 
been  shown  that  mental  labor  does  not  require  an  amount 
of  food  energy  that  is  appreciable  through  calorimetric 
measurements.  Further  experiments  were  conducted  by 
Chittenden  2  with  seven  college  athletes  which  continued 
during  five  months.  In  these  experiments  the  protein 
food  taken  was  deliberately  made  much  below  the  quan- 
tity usually  consumed  at  the  training  table,  and  the  total 
quantity  of  food  eaten  was  also  diminished.  Seven-day 
balance  trials  having  for  their  object  a  determination  of 
the  intake  and  outgo  of  nitrogen  show  that  seven  of  these, 
weighing  from  123  to  171  pounds  apiece,  are  estimated 
to  have  presumably  received  food  varying  in  energy  from 
2174  to  3091  calories.  These  figures  are  much  below  the 
standards  obtained  from  a  study  of  the  actual  dietaries  of 
equally  active  persons  in  ordinary  life. 

192.  Possible  errors.  —  Two  facts  should  be  recognized 
in  discussing  Dr.  Chittenden's  conclusions  ;  first,  his 
athletes  confessedly  ate  less  during  the  periods  when  the 
nitrogen  balance  was  accurately  determined,  and  second,  the 
energy  values  were  estimated.  It  is  unsafe  to  conclude, 

1  "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  I,  pp. 
260-261.  2  "  Physiological  Economy  in  Nutrition,"  pp.  327-454. 


Necessary  Food  Consumption 


191 


TABLE    XXVII 

HEAT  PRODUCTION  (ENERGY  USE)  DURING  24  HOURS  l 
Subjects  in  Fasting  Condition 


PH    Q 

NAME 

P   o 

K 

»«„ 

S5 

s  « 

CONSTITUTION 

2  § 
w  3 

H   °    « 

2  P    . 
P   0 

£ 

w33  ° 

^ffltf 

Rud  

43.2 

1333 

1.29 

Very  small  and  thin. 

Dr  Sch         .... 

48.0 

1214 

1.05 

Small,  thin,  good  muscles. 

Rutt 

53.0 

1527 

1.20 

Poor  in  fat. 

B  

58.0 

1510 

1.08 

Normal. 

Dr.  K  

64.0 

1656 

1.07 

Dr.  M.  L.     .     .     .     . 

67.5 

1608 

0.99 

Poor  in  fat,  very  muscular 

Dr  Jaq  

82.0 

1556 

0.79 

Rich  in  fat,  not  corpulent  ; 

good  muscles. 

HEAT  PRODUCTION  IN  SLEEP  DURING  24  HOURS  l 


i    . 

SJ 

M    O 

CONSTITUTION 

NAME 

Brf 

PS    tD 

8« 

2  g 

f    P    W 
H   °    2 

O   P     • 
J   O   O 

£  " 

BE  o 

offlw 

Dr.  Anderson    .     .     . 

90.4 

1773 

.82 

Small  amount  of  fat,  very 

strong. 

J.  C.  W  
Stud   Md.    .... 

76.0 

72.7 
71.2 

1853 
1798 
1657 

1787 

1.021 
0.99J 
0.95 
1.05 

Medium,  highly  trained. 
Poor    in    fat,    very    good 

Engineer       .... 

muscles. 

Cand,  M.D.      .     .     . 

64.9 

1475 

.95 

Slight,  good  muscles, 

highly 

trained. 

Dr.  Bjerre    .... 

63.0 

1418 

0.94 

Slight,  normal. 

Dr.  Bergman    .     .     . 

57.1 

1560 

1.14 

Slight,  strong. 

1 "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  1,  pp.  260-1. 


192  Principles  of  Human  Nutrition 

therefore,  that  the  energy  values  of  the  average  diet  of  the 
athletes  when  under  observation  was  as  low  as  is  given. 
This  view  is  strengthened  by  the  fact  that  although  Dr. 
Chittenden  estimated  at  1700  calories  the  food-energy 
consumption  of  Mr.  Fletcher,  who  maintained  an  apparent 
body  equilibrium  while  he  was  given  the  "  drastic  exer- 
cises "  of  the  Yale  University  crew,  when  this  subject  was 
tested  in  the  respiration  calorimeter  in  a  state  of  inactivity, 
his  heat  output  was  1896  calories,  536  calories  more  than 
his  food  contained.1  Dr.  Benedict  in  commenting  on  this 
says  with  good  reason  that  Mr.  Fletcher's  use  of  energy 
when  taking  the  Yale  exercises  could  not  have  been  less 
than  3000  calories,  part  of  which  was  at  the  expense  of 
his  body.  The  maintenance  of  a  nitrogen  equilibrium 
and  of  uniform  body  weight,  as  in  Mr.  Fletcher's  case,  is 
not  evidence  that  the  body  has  not  lost  substance,  for 
muscular  exercise  in  excess  of  the  food  supply  is  sustained 
by  the  body  fat  as  long  as  it  lasts,  and  weight  may  be 
maintained  even  during  a  loss  of  body  fat,  for  this  loss  may 
be  replaced  by  water.  Moreover,  the  estimation  of  avail- 
able food  energy  on  the  basis  of  the  average  composition 
and  digestibility  is  a  precarious  method.  Exact  measure- 
ments are  necessary  for  exact  conclusions. 

193.  Minimum  nutrition. — But  after  all,  is  minimum 
nutrition  desirable  ?  (The  question  of  the  desirable  protein 
intake  will  be  considered  later.)  Certainly  much  disease 
is  caused  by  overeating.  Many  persons  should  practice 
greater  moderation  in  satisfying  their  appetite.  Those 
who  take  on  excessive  fat  would  do  well  to  eat  less,  exercise 
freely,  and  thus  draw  upon  the  food  for  the  maintenance 

1  Am.  Jour.  Phys.,  Vol.  16,  p.  433. 


Necessary  Food  Consumption  193 

of  muscular  activity,  thereby  preventing  the  storage  of  fat. 
It  is  especially  true  of  those  who  live  sedentary  lives  and 
store  body  substance  beyond  what  may  be  regarded  as  a 
normal  weight,  that  they  would  do  well  to  be  more  ab- 
stemious. Doubtless  by  so  doing  in  many  cases  bodily 
comfort  would  be  promoted,  the  tendency  to  disease  would 
be  less,  and  mental  efficiency  would  be  increased.  The 
case  is  different  with  that  large  number  of  persons  who 
practically  keep  in  nutritive  equilibrium. 

194.  Energy  requirement  determined  by  energy  out- 
put. —  In  discussing  this  we  must  constantly  keep  in  mind 
the  fundamental  fact  that  "  the  energy  output  is  practically 
the  energy  requirement,"  under  given  conditions,  of  course, 
and  the  expenditure  caused  by  the  muscular  activity  of  a 
particular  individual  cannot  be  reduced  without  affecting 
the  work  done  or  causing  loss  of  body  substance.     Stated 
another  way,  it  is  necessary  to  conclude  that  when  the 
body  is  maintained  in  equilibrium,   neither  gaining  or 
losing,  there  is  an  exact  balance  between  the  intake  of 
available  food  energy  and  the  expenditure  of  energy  on  the 
part  of  the  organism.     If  an  individual  maintaining  this 
balance  is  to  continue  a  given  energy  expenditure  and  not 
lose  flesh,  he  must  continue  to  receive  its  food  equivalent ; 
or  if  he  is  to  eat  less  food  and  not  lose  flesh,  he  must  dimin- 
ish the  energy  expenditure.     The  question  is,  then,  can 
those  of  us  who  are  active  eat  less,  that  is,  can  we  effect  a 
diminution  in  the  necessary  energy  exchange  of  our  bodies, 
and  if  we  can,  how  is  it  to  be  done  ? 

195.  Reduction  of  energy  requirement.  —  Of  course,  if 
the  diet  of  any  person  is  so  light  as  to  cause  a  loss  of 
weight,  then  energy  needs  are  diminished,  because,  other 


194  Principles  of  Human  Nutrition 

things  being  equal,  the  greater  the  body  mass  the  greater 
the  food  needs.  Moreover,  when  less  food  is  eaten,  the 
work  of  digestion  is  lowered.  This  is  a  minor  factor, 
however.  The  most  effective  way  of  materially  diminish- 
ing the  work  of  the  body  is  to  restrict  its  muscular 
exertion;  but  with  a  person  who  continues  a  given  oc- 
cupation, it  is  scarcely  possible  for  him  to  so  modify  his 
activities  that  his  food  needs  are  lowered  to  any  appreci- 
able extent.  If  a  person  undertook  to  restrict  his  daily 
and  habitual  movements,  even  though  they  might  be 
purposeless,  it  would  be  at  a,  sacrifice  of  comfort  and  with 
no  certainty  of  its  accruing  to  his  physical  advantage 
simply  because  it  would  be  possible  to  eat  less. 

It  is  certain  that  a  lower  maintenance  diet  means,  in 
general,  a  lower  range  of  activity  in  some  direction  or 
other,  unless  we  conclude  that  the  human  organism  may 
be  induced  to  take  on  new  metabolic  habits,  with  a  larger 
net  result  of  work  accomplished  in  proportion  to  the  food 
eaten.  If  we  have  confidence  in  the  law  of  the  conserva- 
tion and  correlation  of  energy,  we  must  conclude  that  this 
cannot  happen.  It  has  been  suggested  that  there  is  what 
may  be  called  a  race  habit  in  the  use  of  food.  Doubtless 
this  is  so,  but  it  would  be  absurd  to  expect  that  one  race 
will  accomplish  more  units  of  work  with  a  given  expendi- 
ture of  energy  than  another.  It  maj^  be  true,  however, 
that  the  racial  habits  of  life  or  nervous  temperament  may 
so  differ  as  to  give  one  race  preeminence  in  the  proportion 
of  food  energy  that  is  converted  into  productive  work. 

196.  Relation  of  food  and  body  type.  —  One  question 
has  not  been  answered.  We  do  not  know  what  the  effect 
on  the  physical  type  of  man  would  be  if  generation  after 


Necessary  Protein  Supply  195 

generation  was  to  adopt  food  minima  as  a  practice.  If  we 
reason  by  analogy,  the  results  would  not  be  desirable. 
Farm  animals  are  not  reared  to  their  best  estate  or  made 
most  productive  by  studying  to  reduce  their  rations.  We 
recognize  the  value  of  full-fed  animals.  It  is  fair  to  raise 
the  question  whether  the  full-fed  man,  with  his  reserve  of 
energy  is  not  the  type  upon  which  the  virility,  even  the 
intellectual  strength,  of  a  nation  must  depend. 

C.    THE  NECESSARY  PROTEIN  SUPPLY 

Apart  from  the  question  of  the  total  food  requirements 
of  the  human  body,  there  is  much  discussion  over  the 
necessary  protein  supply.  Investigation  has  shown  there 
i^  a  necessary  daily  minimum  protein  use.  Even  with 
persons  in  starvation,  a  certain  protein  destruction  goes 
on,  which,  after  a  time,  draws  on  the  tissues.  When 
insufficient  protein  is  taken  in  the  food,  the  necessary 
balance  will  be  supplied  from  the  body.  On  the  other 
hand,  where  there  is  no  growth  of  tissue  or  temporary 
storage  of  protein,  any  excess  of  protein  above  this  mini- 
mum requirement  is  also  broken  down.  In  other  words, 
the  body  maintains  a  nitrogen  balance,  the  excretion  of 
nitrogen  compounds  in  the  urine  fluctuating  with  the 
intake  of  protein. 

197.  Fixed  and  circulatory  protein.  —  Bio-chemists 
have  come  to  regard  the  protein  of  the  animal  organism 
as  existing  in  two  general  conditions,  viz.,  what  may  be 
called  the  "  fixed,"  "  stable,"  or  "  tissue  "  protein,  and 
the  "  circulatory  "  or  "  labile  "  protein.  It  is  the  latter 
that  does  not  resist  disintegration,  and  it  probably  consists 
in  part  of  that  surplus  protein  which  is  immediately  derived 


196  Principles  of  Human  Nutrition 

from  the  food  and  which  has  not  become  deposited  in  the 
tissue  form.  This  is  the  type  of  protein  that  fluctuates 
according  to  the  food  supply,  and  it  is  by  the  disintegration 
of  this  that  the  body  keeps  in  protein  balance  when  suffi- 
ciently long  periods  of  time  are  considered.  A  sudden 
increase  of  food  protein  may  cause  a  temporary  storage, 
for  there  appears  to  be  a  "  lag  "  in  the  adjustment  of  the 
supply  to  the  expenditure,  but  the  adjustment  comes 
more  or  less  gradually. 

198.  Protein   standards.  —  The  food  standards  which 
are  based  upon  observations  of  practice  call  for  not  less 
than  100  grams  of  protein  daily  for  professional  men,  and 
175  grams  for  meti  at  severe  labor.     Voit  gave  118  grams 
as  the  standard  for  a  strong  man  doing  moderate  work. 
Notwithstanding  these  estimates,  men  in  various  occupa- 
tions have  been  found  to  maintain  a  protein  balance,  that 
is,  no  loss  of  protein  occurred  from  the  body,  when  the 
intake  was  much  less  than  the  standards  set.    Dr.  Chitten- 
den,  a  teacher,  was  able  after  some  training,  to  keep  in 
protein  equilibrium  on  40  grams  of  protein  per  day.     Five 
of  the  college  athletes  he  experimented  with  even  made 
a  slight  gain  of  protein  (nitrogen)  on  from  55  to  72  grams 
of  protein  daily.     Several  instances  are  on  record  where 
men  of  moderate  size  made  a  daily  use  of  only  from  33 
to  50  grams.     Unquestionably  a  protein  equilibrium  may 
be  maintained,  temporarily  at  least,  on  much  less  of  an 
intake  than  is  called  for  by  the  dietary  standards. 

199.  Demands  on  protein  supply.  —  Is  the  protein  in 
the  dietary  standards  in  excess  of  what  in  a  few  investiga- 
tions has  been  found  to  be  a  minimum  requirement,  neces- 
sary or  even  desirable?    Would  it  be  to  our  advantage  to 


Protein  and  Health  197 

eat  less  meat,  fish,  cheese,  milk,  or  eggs?  We  shall  see 
that  when  an  individual  passes  from  a  state  of  compara- 
tive inactivity  to  severe  labor,  protein  exchange  is  not 
materially  increased,  provided  carbohydrates  and  fats  are 
supplied  in  sufficient  quantity.  In  other  words,  the  sourcel 
of  muscular  energy  is  not  in  the  destruction  of  protein  j 
compounds,  but  may  come  almost  entirely  from  the  oxida- 
tion of  the  non-nitrogenous  parts  of  the  food.  A  large 
protein  supply,  then,  does  not  appear  to  be  necessary  to  the 
laborer,  as  a  means  of  repairing  waste  of  muscle  tissue, 
although  it  must  be  confessed  that  in  ordinary  dietetic 
practice  he  consumes  protein  foods  somewhat  in  propor- 
tion to  the  severity  of  his  labor. 

200.  Protein  and  health.  —  The  arguments  in  favor  of  a 
restricted  consumption  of  protein  are  based  chiefly  on  the 
benefits  to  health.  It  is  urged  that  as  all  protein  wastes, 
of  whatever  kind,  must  be  eliminated  through  the  kidneys, 
a  generous  protein  consumption  places  a  heavy  burden  upon 
these  organs  at  which  they  are  said  to  rebel,  and  there 
occurs  an  accumulation  of  nitrogen  wastes  in  the  organism 
that  is  dangerous  to  health.  Rheumatism  and  gout  have 
been  regarded  as  related  to  uric  acid  accumulation,  and 
nitrogenous  bodies  are  believed  to  often  cause  "auto-intox- 
ication," bringing  on  biliousness  and  low  forms  of  fever. 
Unquestionably  much  physical  suffering  and  disability 
arises  in  these  and  other  ways  from  the  excessive  consump- 
tion of  protein  foods,  especially  meats.  The  question  turns 
on  what  is  excessive.  Are  the  dietary  standards  exces- 
sive? Dr.  Chittenden  claims  for  himself  and  the  other 
subjects  with  whom  he  experimented  that  a  material 
reduction  of  the  protein  intake  resulted  in  a  betterment 


198  Principles  of  Human  Nutrition 

of  condition  both  physical  and  mental.  There  is  also 
much  popular  testimony  to  the  same  effect,  although  the 
most  of  this  relates  to  the  total  food  consumption  rather 
than  to  the  mere  diminution  of  the  protein  intake. 

201.    Arguments   against   minimum   protein   supply.  — 
But  students  of  human  nutrition  do  not  all  agree  that  so 
radical  a  diminution  of  protein  in  the  food  is  desirable. 
n  the  first  place,  there  is  some  reason  for  believing  that 
rotein  serves  the  mature  animal  organism  in  other  ways 
tissue  waste,  and  that  the  physi- 


ological needs  are  less  efficiently  served  when  the  protein 
supply  is  held  down  to  the  minimum  that  just  makes 
good  the  unavoidable  protein  destruction.  General  facts 
of  observation  and  experience  are  cited.  It  is  held  to  be 
significant  that  the  communities  holding  leading  positions 
in  the  world  consume  a  liberal  quantity  of  protein,  or,  con- 
versely, that  communities  with  an  inferior  physical  and 
mental  status  use  a  low  proportion  of  protein  in  the  diet. 
We  certainly  cannot  ignore  the  facts  of  long  continued 
experience.  It  is  asserted  with  great  force,  that  we  do 
not  know  what  would  be  the  effect  of  a  low  protein  diet 
if  continued  through  many  generations.  We  do  know 
that  people  of  great  physical  strength  have  developed 
and  lived  in  whose  diet  animal  foods  occupied  a  promi- 
nent place.  If  we  argue  from  analogies  in  feeding  farm 
animals,  —  and  physically  man  is  an  animal,  —  generous 
protein  feeding  is  desirable  for  the  growth  and  mainten- 
ance of  vigorous  organisms  and  a  satisfactory  rate  of 
production.  It  is  regarded  as  significant  by  one  critic 
of  Dr.  Chittenden  that  all  the  athletes  used  in  his  tests 
returned  to  practically  their  former  diet,  which  they  would 


General  Considerations  199 

hardly  have  been  allowed  to  do  if  the  low  protein  diet 
had  been  found  to  be  so  greatly  superior.  The  question 
is  a  complex  one,  and  is  by  no  means  settled.  Certainly 
no  facts  appear  which  show  with  any  conclusiveness  that 
the  dietary  standard  of  118  grams  of  protein  per  day  for 
a  moderately  active  person  of  average  size  may  not  be 
followed  with  safety  and  advantage  to  health  and 
vigor. 

NoTE.1  —  It  is  probable  that  the  source  of  protein  has  much  to 
do  with  the  efficiency  of  a  given  quantity,  especially  when  the 
purposes  of  growth  must  be  served.  Since  paragraph  159,  p.  152, 
Chap.  VII,  was  written  Osborne  and  Mendel  have  published  the 
results  of  extensive  studies  on  the  efficiency  of  individual  pro- 
teins. The  experimental  animals  used  were  albino  rats,  the 
technique  and  control  being  such  as  to  inspire  confidence  in  the 
data  secured.  The  authors  call  attention  to  the  fact  that  gelatin 
has  long  been  known  as  a  protein  inadequate  of  itself  for  sus- 
taining life.  Other  individual  proteins  can  now  be  studied.  Ob- 
servations were  made  with  rations  containing  the  following  pro- 


experiments  the  failure  to  produce 
growth  or  even  to  permanently  maintain  life,  where  the  artificial 
food  mixture  contained  only  a  single  protein,  was  due  to  the  inad- 
equacy of  the  mixture  of  non-protein  compounds  and  inorganic 
salts  accompanying  the  protein.  Later  experiments  where  the 
single  proteins  were  fed  with  protein-free  milk  (casein  and  lactal- 
bumin  removed)  showed  that  adequate  growth  was  secured  with 
casein,  lactalbumin,  egg  albumin,  edestin,  glutenin,  and  glycinin. 
Growth  was  not  secured  but  life  was  maintained  when  the  follow- 
ing proteins  were  fed  with  protein-free  milk  :  gliadin  of  wheat, 
and  hordein  of  barley,  while  zein  from  corn  proved  to  be  insuffi- 
cient for  the  maintenance  requirement.  It  is  hardly  to  be  ex- 
pected that  these  results  would  have  any  significance  as  related  to 
ordinary  dietaries  that  are  made  up  of  a  mixture  of  animal  and 
vegetable  foods.  It  seems  possible,  however,  that  the  develop- 
ment of  the  human  body  may  be  modified  when  the  diet  is  largely 
of  one  material  such  as  rice  or  corn.  As  a  side  issue,  the  authors 
point  to  the  fact  that  the  synthesis  of  conjugated  proteins  (nucleo 
proteins,  haemoglobin)  from  simple  proteins  and  inorganic  salts 
must  have  taken  place. 

i  Science,  1911,  pp.  722-732. 


CHAPTER  X 

THE    SELECTION   OF    FOOD,  OR    THE    REGU- 
LATION OF  DIET 

IT  is  useless  to  expect  that  the  eating  habits  of  the 
general  mass  of  persons  can  ever  be  brought  to  a  dead 
level  established  by  scientific  principles.  Individual 
tastes  and  physiological  dissimilarities  will  always  play 
an  important  part  in  the  use  of  food,  and  this  fact  should 
have  a  free  recognition.  On  the  other  hand,  we  should 
frankly  admit  the  irrational,  luxurious,  and  health-destroy- 
ing dietetic  habits  in  which  the  American  people  so  largely 
indulge.  Besides,  the  economics  and  sanitation  of  the 
food  supply  are  matters  of  great  importance.  There  is 
every  reason  why  our  use  of  food,  upon  which  our  physical 
welfare  so  fully  depends,  should  be  given  the  same  rational 
consideration  that  we  give  to  business,  education,  or  any 
other  important  relation. 

202.  Limitations  of  food  standards.  —  But  this  does 
not  mean  that  diet  should  be  regulated  by  rule  or  mathe- 
matical formulae;  in  fact,  this  is  not  necessary.  In 
special  cases,  such  as  "  food  cures,"  the  training  table  and 
the  food  supply  of  institutions,  a  careful  consideration  of 
the  composition  and  combination  of  foods  is  wise  and  even 
essential  to  the  best  or  most  economical  results,  but  it  is 
fanciful  to  suppose  that  the  daily  eating  habits  of  the  great 

200 


Classes  of  Food  201 

mass  of  people  will  be  voluntarily  brought  under  scientific 
regulation.  At  the  same  time  it  is  reasonable  to  hope 
that  through  education  and  the  diffusion  of  certain  funda- 
mental principles  and  facts,  a  more  rational  general 
point  of  view  may  b£  established  than  now  seems  to 
prevail. 

The  application  in  a  practical  way  to  the  dietary  of  a 
family  of  the  scientific  facts  and  principles  of  human 
nutrition,  when  the  members  of  the  family  differ  in  age, 
activity,  tastes,  and  food  adaptations,  is  not  a  simple 
matter.  How  shall  the  housewife  meet  the  situation  in  a 
way  that  is  not  burdensome?  Much  will  depend  upon 
her  equipment  of  knowledge.  If  she  is  well  informed  as 
to  the  general  needs  of  the  human  body  in  its  various  ages 
and  conditions,  and  understands  what  nutrients  are  sup- 
plied by  the  different  classes  of  foods,  knowledge  that 
should  be  imparted  to  every  young  woman,  she  will  find 
no  great  difficulty  in  selecting  a  combination  of  foods  that 
is  nutritively  efficient  and  at  the  same  time  is  simple  and 
economical.  She  can  at  least  avoid  the  gross  errors  so 
often  observed  in  the  eating  habits  of  many  families. 
There  are  some  general  facts  that  should  be  kept  in  mind 
as  a  guide  to  practice. 

203.  Classes  of  food.  —  In  order  to  render  clear  state- 
ments that  will  be  made  concerning  the  regulation  of 
diet,  we  should  at  this  point  gain  definite  information 
concerning  the  food-stuffs  from  which  a  diet  may  be 
selected. 

Food  materials  are  classified  in  a  general  way,  and  with- 
out a  very  definite  division  between  the  classes,  into 
watery-foods,  protein- foods,  carbohydrate  foods,  and  fatly 


202 


Principles  of  Human  Nutrition 


foods.  This  does  not  mean  that  some  food  materials  con- 
tain water  and  others  do  not,  or  that  one  class  consists 
wholly  of  protein  or  carbohydrates  or  fat.  To  be  sure, 
the  sugars  and  the  starches  are  wholly  carbohydrate,  and 
butter  and  salad  oil  practically  all  fats;  but  the  great  bulk 
of  food  materials  are  mixtures  of  all  classes  of  nutrients, 
and  we  use  the  classifying  terms  to  indicate  that  a  rela- 
tively large  proportion  of  water  or  protein  or  carbohydrates 
or  fats  is  present  in  the  dry  matter  of  the  class  designated 
by  one  of  these  terms.  The  real  facts  are  best  illustrated 
by  the  following  table  of  selected  foods  arranged  by  classes. 
For  a  fuller  knowledge,  the  full  table  at  end  of  volume 
may  be  consulted. 

TABLE    XXVIII 

CLASSES  OF  FOOD 

Protein  Foods 


WATER 

ASH 

PROTEIN 

CARBO- 
HYDRATES 

FATS 

Sirloin  steak  (free  from 

Per  Cent 
74.  O 

Per  Cent 
i  9 

Per  Cent 
99  i 

Per  Cent 

Per  Cent 
q  i 

Round  steak  (lean)    . 

70.0 

7O  /-» 

1.1 
1  9 

21.3 
9O  9 



7.9 

Q  n 

KO    C 

K   K 

1Q  Q 

9O  & 

Liver 

71  4 

1  4 

21  3 

45 

7  A.  ft 

1    1 

91   ^ 

9  ^ 

Chicken  (broiler)  . 

r^rirJ-fiaVi    ff-rocVi^ 

09  a 

1  9 

Ifi  ^ 

4" 

Pr»rlficVi    ffraaVi^ 

rq  r 

94.  7 

94-  Q 

n  8 

70  A 

i  9 

IQ  7 

7  1 

Lobster    

79.2 

2.2 

16.4 

0.4 

1.8 

70  7 

In 

10  A 

in  ^ 

o/i  9 

q  Q 

9r  Q 

qq  7 

Cheese  (full  cream) 
Milk  (cow's,  average) 

O'l.Z 

87.0 

o.o 

0.7 

^o.y 
3.3 

5.0 

OO./ 

4.0 

Classes  of  Food 


203 


Carbohydrate  Foods 


WATER 

ASH 

PROTEIN 

CARBO- 
HYDRATES 

FATS 

Per  Cent 

Per  Cent 

Per  Cent 

Per  Cent 

Per  Cent 

White  bread      . 
Crackers  

35.3 

68 

1.1 

1  8 

9.2 
107 

53.1 
71  9 

1.3 

8  8 

Gingerbread      . 
Tapioca  pudding   .     . 
Potatoes  (cooked) 
Squash     .     .     . 
Molasses       .... 

18.8 
64.6 
75.5 
88.3 
25  1 

2.9 
0.8 
1.0 
0.8 
32 

5.8 
3.3 
2.5 
1.4 
24 

63.5 
28.2 
20.9 
9.0 
693 

9.0 
3.2 
0.1  , 
0.5 

Honey      ....     . 

18.2 

0.2 

0.4 

81.2  , 

i  o(\  r\ 

k  

Tapioca   ..... 

11.4 

0.1 

04 

880 

0  1 

Apples                     .     . 

846 

03 

04 

142 

0  5 

Fat  Foods 


7Q 

0   Q 

1  Q 

Q£>   0 

Bacon  (smoked)     .     . 

18.8 

4.4 

9.9 



67.4 

Butter 

11  0 

30 

1.0 

85.0 

Salad  oil 

1000 

Watery  Foods 


Asparagus     .... 
Beets  

94.0 

87.5 

0.7 
1.1 

1.8 
1.6 

3.3 
9.7 

0.2 
0.1 

Peas 

746 

1.0 

7.0  t 

16.9 

0.5 

Apples      

84.6 

0.3 

0.4 

14.2 

0.5 

Strawberries      .     .     . 

90.4 

Q9  Q 

0.7 

1  9 

1.0 

A  A 

7.4 

0.6 

O4 

Beef  soup      .... 

QA  O 

11 

f)  C 

n  4. 

Consomme    .... 
Oysters  (edible  portion) 
Milk    ...... 

yo.u 
86.9 
87.0 

2.0 
0.7 

6.2 
3.3 

3.7 
5.0 

1.2 
4.0 

204 


Principles  of  Human  Nutrition 


Dry  Foods 


WATER 

ASH 

PKOTEIN 

CARBO- 
HYDRATES 

FATS 

Per  Cent 

Per  Cent 

PerCent 

Per  Cent 

Per  Cent 

Crackers  (average) 
White  bread      .     . 
Cookies  (molasses) 
Zwieback      .     .     . 
Doughnuts  .     .     . 
Bacon      

6.8 

35.3 
6.2 
5.8 
18.3 
20.2 

1.8 
1.1 
2.2 
1.0 
0.9 
5.1 

10.7 

9.2 
7.2 
9.8 
6.7 
10.5 

71.9 
53.1 
75.7 
73.5 
53.1 

8.8 

1.3 

8.7 
9.9 
21.0 
64.8 

Salt  nnrlr  Cfafi 

7  Q 

q  q 

1  Q 

Ott  0 

Cheese 

342 

3  8 

25  9 

33  7 

Butter 

11  0 

3  0 

1  0 

85  0 

The  foregoing  are  simply  illustrations  of  the  types  of 
foods.  There  are  numerous  combinations  of  the  raw  food 
materials  which  contain  the  nutrients  in  a  great  variety  of 
proportions,  such  as  soups,  breads,  salads,  puddings,  pies, 
and  cakes.  It  is  evident,  however,  that  a  regulation  of 
diet  must  be  accomplished  through  selection  of  the  un- 
cooked materials. 

204.  Facts  for  guidance.  —  The  housewife  who  keeps 
the  following  facts  in  mind  may  combine  foods  in  an 
approximate  way  that  will  fully  meet  the  needs  of  the 
human  organism  of  whatever  age  or  condition. 

l^Fresh  vegetables,  fruits,  milk,  fresh  meats,  fish,  and 
shellfish  contain  large  percentages  of  water. 

^: Bread,  flours  and  meals,  crackers,  breakfast  foods, 
pastry  (mostly),  nuts,  dried  fruits,  cakes,  syrups,  cured 
meats,  cheese,  butter,  contain  relatively  large  percentages 
of  dry  matter. 


The  Selection  of  Food  205 

foods,  such  as  lean  meats  of- -all  kinds,  fish, 
excepting  certain  very  fat  species,  shellfish,  eggs,  cheese,) 
and  milk  furnish  dry  matter  containing  relatively  highf 
percentages  of  prufceiix- 

^t^Legiimes  and  cerlain-iiuts  supply  relatively  more 
protein  than  other  vegetable  foods. 

5/The  cereal  grains,  vegetables,  and  fruits,  while  eoiS 
taining  material  percentages  of  protein,  are  made  up 
largely  of  carbohydrates  or  allied  bodies  having  a  similarj 
nutritive  function. 

6/The  unmodified  foods,  such    as  grains,  vegetables, 

/fruits,  meat,,  eggs,  and  milk,_may  be  depended  upon  to 

•  supply  in  kind  all  the  necessary  elements  to  sustain  the 

growth,  functions,  and  wastes  of  the  human  body.     On  the 

other  hand,  the  foods  which  it  is  proper  to  designate  as 

"  artificial  "  are  not  only  not  essential  to  an  adequate  diet, 

but  they  are  those  which,  when  used  freely,  may  render 

a  diet  very  one-sided  or  deficient. 

7^<?ertain  foods  that  are  manufactured  may  be  en- 
tirely devoid  of  one  or  more  of  the  classes  of  nutrients,  or 
have  a  very  one-sided  composition.  For  instance,  sucfr 
materials  as  corn  starch,  sago,  tapioca,  the  syrups  and 
sugars,  butter,  lard,  and  salad  oils  contain  no  ash  or 
protein,  excepting  that  ash  elements  may  be  present  in 
the  syrups. 

8.  Foods  may  be  so  selected  as  to  give  an  abundant 
supply  of  the  mineral  ingredients}    For  instance,  the  dry] 
substance   of   certain  vegetables   like   asparagus,  lettuce,! 
and  spinach,  and  animal  foods  such  as  eggs  and  beef  extract,  \ 
are  relatively  rich  in  iron  compounds,  just  as  the  dry  sub-   J 
stance  of  leguminous  seeds,  carrots,  and  some  other  vege-  / 


206 


Principles  of  Human  Nutrition 


tables,  milk  and  cheese  is  comparatively  rich  in  calcium 
compounds. 

~9.  Lean. -meats,  milk  and  its  products,  flours  and  meals 
from  the  c^r£al_grains,  and  especially  cereal  preparations 
that  have  been  dextrinized  through  heat  or  malting,  are 
more  easily  and  more  fully  digested  than  the  fibrous  vege- 
table foods. 

205.  Regulation  of  diet  as  to  quantity  of  dry  matter 
eaten.  —  The  ordinary  measure  of  food  consumption 
is  the  bulk  of  material  taken  into  the  stomach.  This 
may  be  a  most  inaccurate  measurement  of  the  actual 
nutriment  consumed.  In  estimating  a  given  ration, 
account  must  be  taken  of  the  amount  of  dry  matter  it 
contains.  While  water  is  an  essential  ingredient  of  our 
food,  and  is  abundant  in  the  human  body,  it  is  not  a 


TABLE  XXIX 

Two  MEALS  OF  EQUAL  WEIGHT,  BUT  GREATLY  UNLIKE  IN 
THEIR  CONTENT  OF  DRY  MATTER 


ORDER  No.  1 

WT. 

DRY 

MATTER 

ORDER  No.  2 

WT. 

DRY 

MATTER 

Clam  chowder 

Oz. 

8 

Oz. 

0904 

Ham  .... 

Oz. 
3 

Oz. 

1.395 

White  bread  . 
Butter 

2 
V<> 

1.294 
0425 

Potato  (boiled) 
\\7hite  bread 

4 
24 

0.976 
1.294 

Strawberries  . 
Sugar  i       .     . 

Cream  1      .     .     • 

4 

M 

2 

0.584 
0.500 
0.600 

Butter  .... 
Apple  sauce  .  .  . 
Crackers  .... 

1 
4 
1 

0.850 
1.556 
0.930 

Total      .... 

17 

4.307 

Cheese  .... 
Cream  2  .  .  .  . 
Sugar  

1 

y2 
.  y* 

0.658 
0.150 
0.500 

Total    .... 

17 

8.309 

1  On  strawberries. 


2  In  coffee. 


The  Selection  of  Food  207 

tissue-builder  in  the  true  sense,  neither  does  it  supply 
energy,  so  that  the  determination  of  food  values  is  basedj 
on  what  is  left  in  an  article  of  diet  after  the  water  is 
eliminated. 

It  is  possible  to  greatly  vary  the  real  supply  of  nutri- 
ment, and  at  the  same  time  maintain  a  good  degree  of 
uniformity  in  the  bulk  or  weight  of  food  eaten.  This 
is  readily  observed  in  an  a  la  carte  restaurant  where  orders 
like  the  two  on  p.  206  are  not  infrequently  noted.  These 
would  have  the  same  weight,  No,  1  being  the  more  bulky, 
but  they  would  be  greatly  unlike  in  their  content  of  dry 
matter. 

If  the  above  foods  were  of  average  composition,  Order 
No.  2  would  supply  more  than  twice  the  dry  matter  in 
Order  No.  1,  although  probably  less  in  bulk.  This  illus- 
trates how  easy  it  is  to  vary  the  diet  in  its  essentials,  and, 
at  the  same  time,  consume  a  satisfying  bulk  of  food. 
Those  who  feel  the  necessity  of  reducing  their  diet  may  do 
so  by  selecting  foods  carrying  a  high  proportion  of  water. 
In  this  way,  the  meal  may  be  made  more  satisfying  than  a 
much  smaller  bulk  of  dry  food,  and  at  the  same  time, 
hold  the  intake  of  nutriment  to  the  desired  minimum. 
The  free  use  of  soups  and  fresh  vegetables  as  against 
meats,  cheese,  bread,  cake,  sweets,  and  similar  materials 
is  wise  for  those  persons  who  have  a  tendency  to  over-" 
indulgence  in  eating.  On  the  other  hand,  men  at  severe 
labor,  such  as  wood  choppers  and  "  river  drivers,"  are  not 
permanently  satisfied  with  a  food  supply  containing 
watery  food  in  any  large  proportion,  but  demand  the 
old-fashioned  diet  of  pork  and  beans  and  flour  bread. 
Invalids  receiving  liquid  preparations  such  as  beef  juice, 


208  Principles  of  Human  Nutrition 

clam  juice,  or  broths  are  not  as  generously  nourished 
as  the  bulk  of  food  would  indicate  to  the  uninformed. 
While  such  preparations  are  admirably  adapted  to  the 
weak  condition  of  a  convalescent  and  to  frequent  feed- 
ing, the  fact  that  they  often  contain  only  from  three 
to  four  per  cent  of  dry  matter  shows  a  very  low  food 
value. 

206.  Regulation  of  diet  with  reference  to  the  combina- 
tion of  nutrients.  —  The  number  of  combinations  of  food 
materials  that  may  be  devised  is  almost  endless,  even  of 
those  that  are  rational  from  every  point  of  view.  It  is 
not  the  purpose  in  this  connection  to  give  numerous  exam- 
ples of  possible  approved  dietaries,  but  simply  to  illustrate 
how  the  principles  herein  set  forth  may  be  applied.  The 
following  menus  for  two  days  are  suggested  by  a  practical 
dietitian  as  examples  of  meals  well  combined,  healthful, 
and  economical.1 

No.  1 

Breakfast  Lunch 

Oatmeal         Milk         Sugar  Pea  soup  Crackers 

Codfish  balls  Macaroni  and  cheese 

Toast  Butter  Graham  bread  and  butter 

Coffee  Tea  Cookies 

Dinner 

Mutton  stew  —  dumplings 
Riced  potatoes,  bread  and  butter 
Poor  man's  rice  pudding 
Coffee 

1  For  a  list  of  raw  materials  required  see  pp.  232-233. 


Combination  of  Nutrients  209 

No.  2 

Breakfast  Dinner 

Pancakes  Syrup  Corned  beef 

Tea  Potatoes  Lima  beans 

Bread  Butter 

Bread  pudding 
Supper 
Baked  omelet 
Creamed  potatoes 

Toast 
Cheese       Milk 

In  day  No.  1  the  mutton,  codfish,  milk  and  cheese  are 
the  distinctively  protein  foods,  and  in  day  No.  2  the  pro- 
teins are  supplied  mainly  from  the  corned  beef,  skimmed 
milk,  eggs  and  cheese.  The  carbohydrates  are  supplied 
in  abundance  from  the  flour,  bread,  vegetables,  and  sugar, 
while  the  fats  are  introduced  mostly  in  the  meats,  cheese, 
and  butter.  Such  combinations  would  not  be  deficient 
in  the  ash  elements. 

The  economy  of  these  food  combinations,  both  nutri- 
tively and  as  to  money  cost,  will  be  discussed  later  (see 
pp.  231-234). 

207.  How  an  ill-considered  diet  may  fail  to  meet 
physiological  requirements.  —  It  is  not  necessary  to 
recount  here  the  number  of  elements  that  are  necessary  to 
the  building  and  maintenance  of  the  human  body,  or  to 
review  the  nutritive  functions  of  the  many  compounds  that 
are  found  in  human  foods,  in  order  to  point  out  possible 
errors  in  the  selection  of  food  and  the  ways  in  which  various 
dangers  may  be  avoided. 


210  Principles  of  Human  Nutrition 

Experience  shows  and  science  corroborates  the  fact,  that 
the  majority  of  persons,  young  and  mature,  are  supplied 
with  nutriment  sufficient  in  quantity  and  kind  to  meet  the 
needs  of  their  bodies  reasonably  well.  60  many  kinds  of 
materials  are  ordinarily  supplied  to  the  table  that  in  many 
families,  at  least,  no  physiological  need  is  left  unsatisfied. 
If  man's  diet  included  only  the  various  products  of  the  soil 
and  of  animal  life  in  an  unmodified  condition  except  the 
cooking,  there  would  doubtless  be  little  danger  that  any 
one,  however  ignorant,  would  suffer  from  incomplete 
nutrition.  But  human  foods  are  now  so  largely  made  up 
of  what  may  be  called  "  artificial "  products,  that  is, 
materials  so  modified  by  some  manufacturing  process  as  to 
almost  wholly  lack  nutrients  of  one  or  more  classes,  it  is  easy 
for  a  child,  or  even  an  adult,  to  so  select  his  diet  on  the 
basis  of  pleasurable  taste  as  to  be  badly  nourished. 

208.  Artificial  foods.  —  It  is  not  difficult  to  illustrate 
how  this  may  happen  by  a  glance  at  what  occurs  in  manu- 
facturing certain  food  materials  that  are  much  used  in 
cookery.  Wheat  flour  enters  largely  into  the  diet  of  every 
family.  In  producing  it  the  outer  coating  of  the  wheat 
kernel  is  removed,  thus  throwing  into  the  milling  offals 
that  portion  of  the  kernel  that  is  most  heavily  charged 
with  the  mineral  ingredients,  particularly  phosphorus, 
potassium,  calcium,  and  magnesium.  The  proportion  of 
digestible  protein  in  white  flour  is  not  less  than  in  whole 
wheat  flour,  as  is  so  often  claimed.  The  starches  arid 
gums,  such  as  corn-starch,  sago,  and  tapioca,  are  separated 
from  the  other  compounds  that  accompany  them  in  the 
plants  in  which  they  are  produced,  and  as  almost  pure  car- 
bohydrates are  extensively  used  in  foods.  The  sugars  in 


Two  Lunches  Compared  211 

the  solid  form  and  in  molasses  and  syrups,  of  which  such 
immense  quantities  are  consumed  in  various  articles  of 
diet  and  in  candies,  are  extracted  from  sugar  cane  and 
the  sugar  beet,  and  to  some  extent  from  the  sap  of  the  sugar 
maple,  the  accompanying  compounds  being  rejected. 
Milk  fat  is  divorced  from  the  other  compounds  of  the 
milk,  and  in  the  form  of  butter  is  eaten  as  an  almost  pure 
fat.  Lard  is  "  rendered "  from  portions  of  the  pig's 
carcass,  and  the  salad  oils  are  extracted  from  olives,  cotton- 
seed, and  other  sources.  These  nearly  pure  forms  of  the 
starches,  gums,  sugars,  and  fats  form  a  large  part  of  such 
foods  as  puddings,  sauces,  cakes,  and  various  pastries.  In 
fact,  many  of  these  articles  of  diet  may  properly  be 
considered  as  concentrations  of  non-nitrogenous  food  com- 
pounds, with  the  partial  elimination  of  the  mineral  ingre- 
dients and  the  proteins.  As  such  combinations  are  delight- 
ful to  the  taste  and  tempt  the  appetite,  they  are  often 
allowed  to  form  a  generous  portion  of  a  meal.  They  are^ 
especially  attractive  to  children;  and  where  these  are 
allowed  an  almost  unrestrained  choice  of  food,  as  is  the  case 
in  many  homes,  such  articles  of  diet  are  a  menace  to  the 
normal  development  and  vigor  of  the  young,  because 
they  are  nutritively  unbalanced  and  may  easily  fail  to 
supply  in  sufficient  abundance  the  needed  elements  of 
growth,  and  may  also  fail  to  furnish  to  the  secretory  glands 
and  tissues  the  compounds  and  chemical  environment 
best  adapted  to  active  metabolism. 

209.  Two  lunches  for  a  boy  compared.  —  Both  children 
and  adults  are  most  fully  nourished  when  their  diet  con- 
sists mainly  of  meat,  fish,  milk,  cereals,  vegetables,  and 
fruits  rather  than  pastries,  cakes,  and  fancy  dishes  so 


212 


Principles  of  Human  Nutrition 


largely  sugars,  starches,  and  fats.  The  foregoing  state- 
ments may  be  illustrated  by  a  concrete  example.  If  an 
average  boy  were  offered  his  choice  between  a  lunch  of 
bread  and  honey,  OF  even  molasses,  or  one  of  bread  and 
milk,  he  would,  without  doubt,  choose  the  former.  Let 
us  see  whether  or  not  his  choice  would  be  wise.  It  is 
estimated  that  he  would  eat  as  follows :  — 


TABLE  XXIX  a 
BREAD  AND  HONEY 


DRY 
MAT- 
TER 

ASH 

PRO- 
TEIN 

CARBO- 
HY- 
DRATES 

FATS 

White  bread    .... 
Honey    . 

Oz. 

4 
3 

Oz. 
2.536 

2454 

Oz. 
.04 
006 

Oz. 
.364 

012 

Oz. 
2.084 

2436 

Oz. 

.048 

7 

4.990 

.046 

.376 

4.520 

.048 

BREAD  AND  MILK 


DRY 

MAT- 
TER 

ASH 

PRO- 
TEIN 

CARBO- 
HY- 
DRATES 

FATS 

White  bread    .... 
Milk       .     .  '  .    .     .     . 

Oz. 

4 
16 

Oz. 

2.536 
2  080 

Oz. 

.04 
112 

Oz. 

.364 

^28 

Oz. 

2.084 
0  800 

Oz. 

.048 
640 

20 

4.616 

.152 

.892 

2.884 

.688 

The  nutriment  in  the  two  combinations  is  greatly 
different.  More  than  90  per  cent  of  the  dry  matter  in  the 
bread  and  honey  consists  of  carbohydrates  and  fats,  while 
in  the  bread  and  milk  the  proportion  is  about  77  per  cent. 


Two  Lunches  Compared  213 

The  combination  of  bread  and  milk  has  three  times  the 
mineral  matter,  over  twice  the  protein,  and  as  much  food 
energy  as  is  found  in  the  bread  and  honey.  There  is  no 
question  but  the  former  would  more  completely  supply  the 
complex  demands  of  a  growing  boy  or  girl.  Those  chil- 
dren who  are  allowed  to  partake  freely  of  sweets,  including 
candy  between  meals,  may  not  be  expected  to  develop  with 
maximum  vigor.  Such  foods  not  only  are  incomplete  in 
themselves,  but  they  spoil  the  appetite  for  the  plainer, 
more  nutritious  articles  of  diet.  Certainly  farm  animals 
could  not  be  developed  to  their  best  estate  on  a  system  of 
feeding  so  irrational,  and  there  is  no  reason  to  suppose 
it  is  possible  with  growing  children. 


CHAPTER  XI 

THE   RELATION  OF  DIET    TO    THE    VARYING 
CONDITIONS  OF  LIFE 

THE  fact  is  almost  self-evident  that,  as  food  supports 
bodily  activity  and  growth,  the  necessary  amount  of  nutri- 
tion must  vary  greatly  with  different  classes  of  persons. 
It  is,  therefore,  no  less  important  than  interesting  to  under- 
stand the  relation  of  age,  size,  sex,  disposition,  occupation, 
and  other  conditions  to  nutritive  demands.  Fortunately  j 
through  the  use  of  the  respiration  calorimeter,  considerable 
reliable  data  have  been  secured  concerning  the  influence  of 
these  factors. 

210.  Childhood.  —  At  no  period  of  life  is  gaseous  ex- 
change (food  oxidation)  so  vigorous  or  so  large  in  pro- 
portion to  weight  as  during  childhood.  Children  are 
peculiarly  active,  being  constantly  in  motion  during  their 
waking  hours.  It  has  been  found  that  a  child  two  and 
one-half  years  old,  weighing  25  pounds  uses,  when  at  rest, 
half  as  much  oxygen  as  an  adult  weighing  150  pounds, 
and  nearly  three  times  as  much  for  each  unit  of  weight. 
/This  means  that  the  demand  for  food  energy  would  be 
fin  these  proportions,  which  for  young  children  of  varying 
ages  is  from  2  to  3  times  as  much  per  unit  of  weight  as 
\Jt  is  for  adults. 

The  following  table  shows  very  clearly  how  age  affects 
metabolic  activity:  — 

214 


Childhood  —  Old  Age 


215 


TABLE    XXX 

OXYGEN  USE  PER  MINUTE  (ENERGY  REQUIREMENT)  FOR  PER- 
SONS OF  DIFFERENT  AGES1 


RELATIVE  VALUE  OXYGEN 

CONSUMPTION  BY  BOYS 

Age 

Weight 

Oxygen  con- 

Oxygen use 

Per  Kg.  of 

Per  sq.  meter 

Yrs. 

,Kg. 

sumed,  C.C. 

per  Kg.  weight 

weight 

of  surface 

2^ 

11.5 

112.2 

9.76 

285 

160 

6 

18.4 

139.9 

7.61 

223 

145 

9 

21.8 

148.0 

6.79 

199 

137 

14 

36.1 

188.1 

5.21 

152 

125 

17 

44.3 

212.7 

4.80 

140 

123 

22-43 

66.7 

227.9 

3.41 

100 

100 

(adults) 

It  appears  that,  whether  we  consider  weight  or  body 

surface,  the  child  appropriates  more  oxygen,  that  is,  gives 

off  more  heat  per  unit  of  weight,  or  of  surface,  than  either 

the  adult  or  the  aged.     Besides,  the  rapidly  developing 

child  stores  in  his  tissues  protein  and  inorganic  salts  which 

must  come  from  the  food.     For  these  reasons  the  liberal, 

and    sometimes    seemingly    excessive,    amounts    of   food 

eaten  by  children,  especially  between  the  ages  of  ten  and 

sixteen,  are  not  irrational,  and  those  who  dictate  school 

dietaries  should  keep  these  facts  in  mind. 

--     211.    Old  age.  —  With  advancing  years,  generally  after 

I  the  age  of  70  or  75  is  passed,  there  is  a  marked  decrease 

!    in  vitality  and  bodily  activity.     The  demand  for  food  is 

[^correspondingly  diminished.     Von  Noorden 2  states,  on  the 

basis  of  exact  observations,  that  the  gaseous  exchange  is 

1  "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  I,  p.  268. 

2  Loc.  cit.,  p.  267. 


216 


Principles  of  Human  Nutrition 


found  to  be  about  20  per  cent  less  with  old  persons  than 
with  those  in  middle  life.  This  refers  evidently  to  the 
resting  condition.  There  is  no  definite  point  at  which 
"  old  age  "  begins,  and  the  stage  of  life  at  which  metabolic 
activity  starts  on  the  down  grade  varies  with  different 
persons. 

212.  "Weight.  —  The  amount  of  food  required  to  sus- 
tin  persons  in  a  resting  condition  increases  with  their 
weight,  though  not  proportionately,  that  is,  a  heavy  man 
idoing  no  work  uses  more  total  food  than  a  light  one,  but 
he  uses  less  per  pound  of  weight.  The  energy  demand  for 
•24  hours  has  varied  in  experimental  observations  from 
9  calories  per  pound  of  body  weight  with  large  individuals, 
to  14  calories  with  small ;  but  it  only  requires  30  per  cent 
or  40  per  cent  increase  of  energy  expenditure  when  the 
weight  doubles.  The  energy  use  is  more  nearly  propor- 
tional to  body  surface. 

TABLE    XXXI 
EFFECT  OF  WEIGHT  ON  ENERGY  USE 


PERSONS  IN  ABSOLUTE  REST 

PERSONS  ASLEEP 

Weight 
Kg. 

Calories  in 
24  Hr. 

Energy 
used  per 
Kg.  of 
weight  in 
24  Hr. 

Weight 
Kg. 

Calories  in 
24  Hr. 

Energy 
used  per 
Kg.  of 
weight  in 
24  Hr. 

82.0 

1556 

19.0 

90.4 

1773 

19.6 

73.0 

1584 

21.7 

83.5 

1670 

20.0 

67.5 

1621 

24.0 

76.0 

1853 

24.4 

50.8 

1315 

25.9 

62.5 

1431 

23.0 

48.0 

1214 

25.6 

57.2 

1560 

27.2 

43.2 

1333 

30.9 

55.0 

1590 

29.0 

Weight  — Sex 


217 


The  above  table  l  illustrates  clearly  the  facts  that  have 
been  stated.  One  exception  should  be  made  to  these 
general  statements,  viz.,  that  increased  weight,  due  to  the 
laying  on  of  fat,  does  not  cause  an  increase  of  total  energy 
used  by  the  resting  individual.  If  the  obese  person  is 
active  or  does  external  work,  then  he  uses  more  energy 
because  more  is  required  to  move  the  body  around. 

213.  Sex.  —  There  is  a  belief  that  men  require  more 
food  than  women ;  and  if  this  refers  only  to  total  food  con- 
sumption, it  is  true,  because  men  weigh  more  generally, 
are  more  active  physically,  and  perform  more  external 
work.  It  is  not  true,  however,  when  we  consider  only  the 
demands  for  the  maintenance  of  what  may  be  called 
physiological  activity.  Investigation  shows  that  when 
the  oxygen  use  of  men  tand  women  of  similar  weight  in  a 
resting  condition  is  compared,  the  gaseous  exchange  is 
practically  the  same. 

TABLE    XXXII 

ENERGY  EXCHANGE  (OXYGEN  USE)  OF  MEN  AND  WOMEN  IN 
RESTING  STATE2 


WOMEN 

MEN 

Weight 
Kg. 

Oxygen  used  per  Kg. 
per  minute 
C.C. 

Weight 
Kg. 

Oxygen  used  per  Kg. 
per  minute 
C.C. 

oc  r 

4  or  1 

48.7 

4.03  j  ^° 

43.2 

4.53 

54.0 

3.91 

53.4 

3.93 

61.7 

3.79 

58.0 

3.81 

68.0 

3.40 

66.7 

3.42 

1  "  Metabolism  and   Practical    Medicine,"  Von  Noorden,  Vol.  I,  pp. 
260-261.  2  Loc.  cit.,  p.  270. 


218  Principles  of  Human  Nutrition 

Of  course,  when  laboring  the  additional  oxygen  consump- 
tion is  proportional  with  both  sexes  to  the  work  performed, 
and  because  man  is  in  a  general  way  of  higher  muscular 
development  than  woman,  he  uses  a  much  larger  total 
energy.  It  has  been  claimed  that  trained  muscles,  even 
when  not  in  use,  have  greater  metabolic  activity  than  the 
untrained.  The  similarity  of  oxygen  use,  per  unit  of 
weight,  by  the  two  sexes  does  not  sustain  this  con- 
clusion. ^ 

214.  Disposition.  — ^JThe  temperament  of  an  individual 
has  much  to  do  with  his  food  requirements)     Persons  of  a 
sanguine  type,  being  more  active,  use  more  energy  than 
the  phlegmatic.     Bodily  movement,  whether  deliberate,  or 
due  to  nervous  activity,  constitutes  work,  and  must  be 
sustained  by  an  equivalent  of  energy  derived  either  from 
food  or  body  substance. 

215.  Work.  —  All  activity  of  the  human  body,  whether 
in  the  maintenance  of  its  functions  or  in  the  performance 
of  labor,  is  work.     The  forcing  of  the  blood  through  the 
arteries  and  veins,  the  digestion  of  food  and  its  assimila- 
tion, we  speak  of  as  intgxnal  work,  while  walking,  running, 
lifting,   the  use  of  tools,   the  moving  about  of  various 
objects,  and  other  forms  of  visible  physical  activity  are 
designated  as  external  work.      The  two  forms  of  work  may 
also  be  classified  as  physiological  and  mechanical.     Nothing 
in  nutrition  is  more  important  than  the  relation  of  food  to 
work.      This  is  true,  not  only  because  a  larger  proportion 
of  the  nutriment  we  take  is  expended  in  sustaining  our 
external    activities,   but   because  we  should   understand 
the  conditions  bringing  about  an  unnecessary  expendi- 
ture  of   food   energy.     Indeed,    outside   of   the    storage 


Effect  of  Work 


219 


of  body  substance,  which  amounts  to  but  little  except 
in  the  case  of  the  young,  all  food  energy  goes  to  sustain 
work,  either  physiological  or  mechanical.  In  this  con- 
nection, it  is  proposed  to  discuss  only  the  relations  of 
food  to  mechanical  work. 

216.  Increased  use  of  oxygen  from  work.  —  No  one 
can  have  failed  to  notice  that  physical  exertion,  especially 
if  it  is  quite  severe,  is  attended  with  more  rapid  breathing, 
a  quicker  pulse,  and  in  warm  weather  a  flushed  face  and 
abundant  perspiration.  An  interesting  table  which  has 
been  compiled  from  data  given  by  Benedict  and  Carpenter l 
shows  the  relation  of  pulse-beat  to  heat  production  and 
carbon-dioxid  elimination :  — 


TABLE    XXXIII 


INCREASED 
CARBON  DIOXID 

INCREASED 
HEAT  PRODUCTION 

INCREASED 
PULSE  BEAT 

Per  Cent 

Per  Cent 

Per  Cent 

38.9 

52.0 

35.7 

8.9 

10.2 

16.1 

29.0 

31.2 

19.6 

49.2 

53.0 

22.9 

37.9 

34.5 

12.9 

13.0 

13.1 

21.1 

30.0 

38.0 

25.0 

There  is  an  entirely  rational  explanation  for  these  phe- 
nomena. Increased  work  requires  an  increased  expendiA 
ture  of  energy,  that  is,  an  increased  use  of  oxygen  forj 

1  "  Metabolism   and  Energy  Transformations  of  Healthy  Man  during 
Rest,"  p.  250. 


220  Principles  of  Human  Nutrition 

Developing  the  potential  energy  of  the  absorbed  food.  As 
heat  is  the  final  or  waste  product  of  muscular  energy,  an 
increase  of  mechanical  work  performed  by  the  muscles 
causes  an  increase  of  heat,  which  must  be  radiated  from 
the  body.  The  relation  of  muscular  exercise  to  the  use  of 
oxygen  and  heat  production  is  made  clear  by  the  following 
table  l  (Sitting  =  100) :  — 

TABLE    XXXIV 

EFFECT  OF  MUSCULAR  EXERCISE  ON  ENERGY  USE 


CARBON  Di- 

OXTGEN 

HEAT 

ELIMINATED 

ABSORBED 

PRODUCED 

Per  Cent 

Per  Cent 

Per  Cent 

Man  at  rest,  sleeping       .... 

70 

79 

73 

Man  at  rest,  awake,  sitting      .     . 

100 

100 

100 

Man  at  rest,  standing      .     .     .     . 

112 

116 

117 

Man  at  severe  muscular  exercise  . 

746 

786 

673 

Above  eight  times  more  oxygen  is  used,  and  seven  times  more 
heat  evolved  during  heavy  work  than  during  rest. 

217.  Increased  respiration  and  blood  flow.  —  For  these 
reasons,  there  occurs  more  frequent  respiration  and  a 
more  rapid  passage  of  the  blood  through  the  lungs  where 
it  comes  in  contact  with  the  respired  air.  Still  further, 
the  blood  is  more  fully  thrown  to  the  surface  of  the  body 
where  it  may  cool  more  rapidly,  and  perspiration  also  occurs 
in  order  that  its  evaporation  may  aid  in  ridding  the  body 
of  the  excess  of  heat  (see  p.  168).  All  this  means  more 
food,  somewhat  in  proportion  to  the  work  done,  the 

1  Loc.  cit.,  p.  252. 


Energy  Efficiency  with  Man  221 

energy  of  which  is  expended  not  only  to  carry  on  external 
work,  but  also  in  part  to  support  the  work  attending  the 
increase  of  breathing  and  blood  flow.  ^More  external 
work  causes  more  physiological  or  internal  work\ 

Additional  data  may  be  cited  to  support  the  above 
statements.  In  the  case  of  two  men,  it  was  found  that  in 
climbing  up  a  steep  incline  the  inspired  air  increased  not 
less  than  five  times  in  volume  over  the  use  when  resting. 
When  a  person  is  walking  rapidly  or  cycling,  the  number 
of  respirations  per  minute  is  at  least  doubled,  and  the 
depth  of  respiration  is  increased  several  times,  so  that  the 
volume  of  each  breath  becomes  greater  than  under  rest 
conditions.  Even  the  work  of  dressing  and  undressing, 
with  the  attendant  influence  of  a  period  of  nakedness, 
caused  in  twenty-one  observations  an  average  increase  in 
oxygen  use  of  34  per  cent  and  an  increase  in  heat  radiation 
of  18  per  cent.1 

218.  Fuel  efficiency  with  man.  —  Measurements  of  the 
oxygen  consumption  under  various  conditions  show  that  one 
foot-pound  increase  of  mechanical  labor  costs  in  extra  food 
energy  approximately  the  equivalent  of  three  foot-pounds 
of  food  energy,  that  is,  the  factor  of  efficiency  of  human 
food  as  fuel  is  about  33  per  cent.2    This  shows  that  the 
living  human  machine  is  relatively  a  most  efficient  one. 
Practically  the  same  factor  holds  for  work  animals. 

219.  How  fuel  efficiency  is  modified.  —  Several  condi- 
tions materially  modify  this  factor  of  efficiency.     When  a 

1  "  Metabolism  and  Energy  Transformations  of  Healthy  Man  during 
Rest,"  Benedict  and  Carpenter,  p.  247. 

2  Benedict  and   Carpenter   calculate  the  factor  of  efficiency  to  be 
20.9  per  cent,  that  is,  that  proportion  of  excess  food  energy  above  main- 
tenance is  realized  in  labor  performed. 


222  Principles  of  Human  Nutrition 

person  takes  up  mechanical  operations  with  which  he  is 
not  familiar,  or  enters  upon  work  that  exercises  a  new  set 
of  muscles,  a  unit  of  work  accomplished  costs  more  in  food 
energy  than  is  the  case  with  operatives  whose  muscles  are 
trained  to  do  a  particular  thing.  Trained  workmen  will 
do  a  given  amount  of  labor  on  less  food  than  the  untrained. 
Very  strenuous  exercise,  like  athletic  contests,  is  wasteful 
of  food  energy.  The  general  rule  is  that  the  energy  cost 
of  a  unit  of  work  increases  with  the  rate  of  work  above 
what  would  be  the  natural  movement.  The  figures  of 
the  table  on  the  following  page  show  this. 

Unnaturally  slow  movements  also  are  expensive  of 
energy.  After  a  continuance  of  the  same  labor  for  hours, 
there  is  an  increase  in  the  energy  expenditure  per  unit  of 
work  performed,  and  fatigue,  whether  it  comes  after  a 
shorter  or  longer  time,  has  a  similar  effect. 

Economy  in  the  use  of  the  energy  that  the  food  supplies 
to  the  body,  which  is  equivalent  to  economy  in  the  use  of 
the  body  itself,  is  most  fully  secured  when  the  movements 
in  labor  are  at  the  natural  rate,  neither  hurried  nor  re- 
strained, and  when  periods  of  intense  effort  do  not  occur, 
and  when  labor  is  not  too  long  continued  and  is  not  carried 
to  the  point  of  extreme  fatigue.  In  considering  the  gen- 
eral nature  of  the  diet  for  sustaining  work,  it  should  be 
remembered  that  the  non-nitrogenous  constituents  of  the 
food,  the  carbohydrates  andjats,  furnish  the  main  supr 
ply  of  energy  (see  pp.  156,  171). 

220.  Obesity.  —  Obesity,  or  the  excessive  accumulation 
of  body  fat,  is  an  occasion  of  great  discomfort  to  many 
persons.  The  intense  desire  of  the  excessively  corpulent 
to  be  freed  from  this  condition  has  opened  the  way  for  the 


Conditions  Affecting  Food  Efficiency          223 


TABLE  XXXV 

ENERGY  AND  FOOD  REQUIREMENTS  OF  A  MAN  (70  KILOGRAMS 
WEIGHT  WITH  CLOTHING)  FOR  DIFFERENT  KINDS  OF  MUSCU- 
LAR WORK1 


, 

INCREASE  OP  METAB- 

OLISM DURING 

ENERGY  EXPENDI- 

ONE HOUR'S  WORK 

MUSCULAR  WORK  PER  HOUR 

TURE  PER 

UNIT  OP  WORK 

Gms.  Fat 

Cal. 

used  up 

3.6  kilometers  over  level  road    . 

40.3  per  km. 

144 

16 

6.0  kilometers  over  level  road    . 

47.2  per  km. 

283 

30 

8.4  kilometers  over  level  road    . 

78.6  per  km. 

660 

70 

6.0  kilometers  over  level  road, 

with  25  kilogram  load   .     .     . 

64.1  per  km. 

385 

41 

4.8   kilometers  over  level   road 

with  25  kilogram  load  . 

59.3  per  km. 

285 

30 

Climbing  300  meters  (30  per  cent 

gradient;  easy  climb)     .     .     . 

49.0  per  100  m. 

147 

16 

Climbing  300  meters,  stiff  climb 

(over  30  per  cent)     .... 

58.0  per  100  m. 

174 

18 

Ascent  of  stair  —  300  meters  in 

a  distance  of  3000  meters—  10 

per  cent  rise     

89.0  per  100  m. 

267 

28 

9  kilometers  cycle  ride  on  level 

road  

20.3  per  km. 

183 

19 

15  kilometers  cycle  ride  on  level 

313 

33 

road    

20.8  per  km. 

22  kilometers  cycle  ride  on  level 

25.9  per  km. 

571 

60 

9  kilometers  cycle  ride  with  3  per 

cent  ascent       .... 

38.3  per  km. 

345 

36 

15  kilometers  cycle  ride  on  level 

road,  with  a  head-  wind  of  10 

meters  per  second     .... 

40.1  per  km. 

601 

64 

1  "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  I,  p.  229. 


224  Principles  of  Human  Nutrition 

sale  of  "  fat  cures  "  that  mostly  deplete  the  store  of  cash 
rather  than  of  adipose  tissue. 

It  seems  reasonably  certain  that  in  a  large  percentage 
of  cases  the  cause  and  cure  of  obesity  are  entirely  within 
the  control  of  the  afflicted  individual.  With  many  obese 
persons,  perhaps  a  majority,  the  laying  on  of  excessive  fat 
is  the  result  of  a  disparity  between  the  food  consumed 
and  the  energy  expenditure.  In  other  words,  certain 
individuals,  especially  men  in  the  professions  not  re- 
quiring physical  activity  and  those  doing  office  work 
at  a  desk,  eat  more  than  is  needed  to  sustain  the 
energy  expenditure.  It  is  noticeable  that  when  an 
individual  becomes  less  active  without  diminishing  his 
food  he  grows  fatter,  and  the  same  occurs  with  an  in- 
crease of  food  without  a  corresponding  increase  in  the 
physical  activity. 

f  The  remedy  for  obesity  with  individuals  whose  metabo- 
lism is  normal  is  either  less  food  or  more  exercise!)  A 

y  — ' 

Deduction  in  the  food  taken  may  require  a  rigorous  con- 
trol of  appetite,  especially  at  first,  but  after  a  time  the 
eating  habit  will  probably  become  readjusted.  A  material 
increase  in  physical  exercise  will  accomplish  the  same  result 
as  a  decrease  of  tfie  food  taken. 

It  does  not  now  seem  possible  to  explain  all  cases  of 
corpulency  on  the  basis  of  overeating  or  deficient  physical 
exercise.  These  instances  where  very  corpulent  persons 
maintain  their  weight  without  loss  on  an  amount  of  food 
less  than  the  customary  requirement  for  such  individuals, 
laying  on  of  fat  by  animals  on  which  castration  or  ovari- 
otomy has  been  performed,  and  the  influence  of  life  condi- 
tions with  women,  seem  to  indicate  a  modified  metabolism. 


Obesity  225 

Studies  of  such  cases  of  obesity  have  so  far  failed  to  estab- 
lish the  fact  of  abnormal  life  processes,  for  the  use  of  oxy- 
gen (energy  exchange),  protein  metabolism,  and  digestion 
appear  to  have  been  normal.  An  explanation  of  all  cases 
of  obesity  does  not  seem  to  have  been  reached. 


CHAPTER  XII 
FOOD    ECONOMICS 

A.  REGULATION  OF  DIET  WITH  REFERENCE  TO 
ECONOMY  OF  EXPENDITURE 

THE  cost  of  a  meal  for  an  individual  or  a  family  is  made 
up  of  two  main  factors:  the  money  cost  of  the  raw  food 
materials,  and  the  time  and  other  expense  required  for 
preparing  and  serving  the  food.  In  both  these  directions 
considerations  of  economy  seem  to  have  very  little  weight 
with  the  average  American  family  as  compared  with  either 
sensuous  desire  or  habits  that  are  determined  by  custom 
and  social  demands.  Well-to-do  Americans  extravagantly 
satisfy  epicurean  tastes,  and  their  menus,  when  rationally 
judged,  are  seen  to  be  more  luxurious  and  wasteful  than 
almost  any  other  department  of  family  expenditure.  Even 
families  of  the  middle  class  that,  because  of  moderate 
means,  feel  the  necessity  of  practicing  rigid  economy  in 
dress,  house  furnishing,  education,  reading  matter,  and 
social  life  are  often  extravagant  in  the  purchase  of  table 
supplies,  though  ignorantly  so,  perhaps.  The  fact  is,  we 
are  so  accustomed  to  certain  eating  habits  that  we  do  not 
realize  how  unnecessarily  expensive  they  are. 

221.  The  cost  of  raw  food  materials.  —  The  proper 
basis  for  estimating  the  relative  cost  of  nutriment  in  the 
various  raw  materials  is  the  amount  of  energy  that  may 

226 


Cost  of  Raw  Food  Materials  227 

be  bought  in  the  edible  food  solids  of  different  materials 
for  a  unit  sum  of  money.  Many  articles  of  food  as  pur- 
chased are  made  up  in  part  of  substance  that  is  not  edible, 
as,  for  instance,  the  bones  and  legs  of  a  dressed  fowl,  the 
skin  and  bones  of  a  fish,  or  the  paring  and  core  of  an  apple. 
AD  raw  food  materials,  with  very  few  exceptions,  contain 
water  varying  in  proportion  from  5  per  cent  or  less  to  over 
90  per  cent.  Both  the  refuse  and  vwater  must  be  sub- 
tracted from  the  total  weight  in  order  to  learn  the  weight 
of  edible  solids.  The  following  table  shows  that  a  pound 
of  bluefish  as  purchased  was  made  up  of  .486  pound  of 
refuse,  .403  pound  of  water  in  the  edible  portion,  and 
.111  pound  of  edible  solids,  this  amount  of  solids  having 
a  food  energy  equal  to  210  calories.  At  18  cents  a  pound 
for  the  fish  as  purchased,  one  dollar  would  buy  only  .61 
pound  of  edible  food  solids.  In  comparison  with  this, 
wheat  flour  has  no  refuse,  and  in  one  pound  only  .128 
pound  of  water,  leaving  .872  pound  of  edible  solids,  con- 
taining energy  equal  to  1640  calories.  At  3.4  cents  per 
pound  for  the  flour,  one  dollar  would  purchase  25.6  pounds 
of  edible  solids  as  against  .61  pound  in  the  bluefish.  This 
means  that  at  the  prices  given  one  dollar  will  purchase 
about  forty-two  times  as  much  edible  food  solids  in  wheat 
flour  as  in  bluefish.  But  a  comparison  on  the  basis  of  the 
weights  of  edible  solids  purchased  for  a  unit  sum  of  money 
is  inaccurate  and  misleading,  because  the  energy  value  of 
the  edible  solids  in  different  foods  is  greatly  unlike.  The 
water-free  edible  nutrients  of  bacon,  for  instance,  would 
furnish  over  90  per  cent  more  energy  from  a  unit  weight 
than  would  the  nutrients  of  wheat  flour.  For  this  reason 
our  comparison  must  be  made  on  the  basis  of  the  energy 


228 


Principles  of  Human  Nutrition 


purchased  in  the  edible  food  for  one  dollar.  For  blue- 
fish  this  would  be  1166  calories  and  for  wheat  flour  48,230 
calories. 

The  table  which  follows  has  been  made  up  from  the 
analyses  and  energy  values  given  in  the  revised  edition  of 
Bulletin  28,  O.E.S.,  U.  S.  Department  of  Agriculture, 
and  the  prices  are  those  at  which  foodstuffs  were  sold  in 
the  city  of  Geneva,  N.  Y.,  during  July,  1910.  Food  prices 
vary  from  year  to  year  and  in  different  localities,  but  the 
figures  given  indicate  in  a  general  way  the  cost  of  nutriment 
from  the  several  classes  of  foods. 

TABLE  XXXVI 

COST  OF  NUTRIENTS  IN  VARIOUS  HUMAN  FOODSTUFFS 


NAME 

POUND 
PRICE 

REFUSE 
IN  ONE 
POUND 

WATER 
IN  ONE 
POUND  OF 
EDIBLE 
PORTION 

EDIBLE 
SOLIDS 
IN  ONE 
POUND 

EDIBLE 
SOLIDS 

FOR   $1.00 

FOOD 
ENERGY 

FOR   $1.00 

Cents 

Pounds 

Pounds 

Pounds 

Pounds 

Calories 

Corn  meal     .     . 

3.0 



0.125 

0.875 

29.17 

55,166 

Wheat  flour       .     . 

3.4 



0.128 

0.872 

25.65 

48,230 

Rolled  oats(in  bulk) 

5.0 



0.077 

0.923 

18.46 

37,000 

Hominy   .... 

5.0 



0.118 

0.882 

17.64 

33,000 

Sugar        .... 

6.0 





1.00 

16.66 

31,000 

Molasses  (can) 

5.0 



0.251 

0.749 

14.96 

25,800 

Lard    

18.0 





1.00 

5.55 

23,444 

White  bread      .     . 

5.33 



0.353 

0.647 

12.13 

22,790 

Cookies    .     . 

10.0~ 



0.081 

0.919 

9.19 

19,100 

Crackers 

11.0 



0.068 

0.932 

8.48 

17,320 

Pork  (fat)     .    •-.',. 

18.0 

0.081 

0.159 

0.760 

4.25 

16,390 

Corning  beef 

(cheap)      .     .     . 

8.0 

0.055 

0.561 

0.384 

4-.80 

14,815 

Coffee  cake  .     .     . 

14.0 



0.213 

0.787 

5.62 

11,609 

Butter      .... 

32.0 



0.110 

0.890 

2.78 

11,265 

Mutton  chops  .     . 

14,0 

0.148 

0.404 

0.448 

3.20 

11,250 

Cheese,  full  cream 

18.0 



0.342 

0.658 

3.65 

10,833 

Bacon       .... 

25.0 

0.087 

0.184 

0.729 

2.54 

10,732 

Milk 

3.67 

0.870 

0.130 

3.54 

8.855 

Ham,  fresh  .     .    ,. 

0.103 

0.451 

0.446 

2.48 

Ojt  lttj£ 

8,444 

Grapes     .... 

4^0 

0.250 

0.58 

0.170 

4.25 

8,375 

Cheap  and  Costly  Foods 


229 


COST    OF    NUTRIENTS    IN    VARIOUS    HUMAN    FOODSTUFFS  — 
Continued 


NAME 

POUND 
PRICE 

REFUSE 
IN  ONE 
POUND 

WATER 
IN  ONE 
POUND  OF 
EDIBLE 
PORTION 

EDIBLE 
SOLIDS 
IN  ONE 
POUND 

EDIBLE 
SOLIDS 

FOR   $1.00 

FOOD 
ENERGY 

FOR    $1.00 

* 

Cents 

Pounds 

Pounds 

Pounds 

Pounds 

Calories 

Ham,  smoked    .     . 

22.0 

0.122 

0.358 

0.520 

2.36 

7,600 

Pork,  roast  .     .     . 

18.0 

0.193 

0.408 

0.399 

2.22 

7,444 

Plums       .... 

5.0 

0.05 

0.745 

0.205 

4.10 

7,400 

Corning  beef,  good 

18.0 

0.055 

0.561 

0.384   - 

2.13 

6,583 

Rib  roast,  beef 

20.0 

0.201 

0.453 

0.346 

1.73 

5,550 

Apples      .... 

4.0 

0.250 

0.633 

0.117 

2.92 

5,500 

Lamb  chops 

25.0 

0.148 

0.453 

0.399 

1.60 

5,260 

Steak,  round 

20.0 

0.072 

0.607 

0.321 

1.60 

4,475 

Steak,  porterhouse 

25.0 

0.127 

0.524 

0.349 

1.40 

$~44g' 

Eggs    ....    •;• 

17.0 

0.112 

0.655 

0.233 

1.37 

3j735 

Corn,  green,  canned 

12.5 



0.761 

0.239 

1.91 

3.B415 

Fish,  salt      .     ..'  . 

15.0 

0.016 

0.548 

0.436 

2.90 

3,635 

Turkey     .... 

30.0 

0.227 

0.424 

0.349 

1.16 

3,585 

Tongue,  beef     . 

16.0 

0.265 

0.518 

0.217 

1.36 

3,406 

Chicken,  canned    . 

50.0 



0.469 

0.531 

1.06 

3,310 

Ham,  deviled     . 

60.0 



0.441 

0.559 

0.93 

2,983 

Tomatoes,  canned 

4.0 



0.940 

0.060 

1.50 

2,625 

Halibut    .... 

18.0 

0.177 

0.619 

0.204 

1.13 

2,611 

Fowls       .... 

30.0 

0.259 

0.471 

0.270 

0.90 

2,583 

Liver        .... 

25.0 



0.714 

0.286 

1.14 

2,460 

Trout  (lake)      .     . 

18.0 

0.485 

0.366 

0.149 

0.83 

2,139 

Raspberries        .     » 

15.0 



0.840 

0.160 

1.07 

2,066 

Oranges    .     .     .1. 

8.33 

0.270 

0.634 

0.096 

1.15 

2,041 

Mackerel       .     . 

18.0 

0.447 

0.404 

0.149 

0.83 

2,027 

White  fish     ... 

18.0 

0.535 

0.325 

0.140 

0.78 

1,805 

Peas,  green,  canned 

15.0 



0.853 

0.147 

0.98 

1,700 

Oysters    .     .    /.     . 

15.0 



0.883 

0.117 

.580 

1,533 

Strawberries      .     , 

12.5 

0.05 

0.859 

0.091 

0.73 

1,400 

Bluefish    .... 

18.0 

0.486 

0.403 

0.111 

0.61 

1,166 

Chicken,  broilers   . 

50.0 

0.446 

0.437 

0.147 

0.29 

590 

Beans,  string, 

canned      .     .     . 

16.5 



0.937 

0.063 

0.38 

575 

Lobster,  whole 

35.0 

0.617 

0.307 

0.076 

0.22 

400 

222.  Cheap  and  costly  foods.  —  This  table  reveals 
several  interesting  and  important  facts.  It  is  emphatically? 
true  that  at  present  prices  the  products  of  plant  growth,  such,, 
as  flours,  meals,  rolled  oats,  hominy,  and  sugar  are  by  far  the^ 


230  Principles  of  Human  Nutrition 

cheapest  source  of  nutrition.  Among  animal  foods  pork  and 
dairy  products  supply  the  cheapest  nutriment,  excepting 
possibly  mutton.  While  the  public  might  concede  the 
relative  cheapness  of  pork  products,  the  general  impression 
appears  to  be  that  milk,  butter,  and  cheese  are  compara- 
tively expensive,  which  is  not  true  at  the  present  time. 
The  most  costly  foods  of  plant  origin  as  a  source  of  energy 
are  certain  fresh  and  canned  vegetables  and  some  fruits, 
including  string  beans,  peas,  tomatoes,  strawberries,  and 
raspberries.  It  should  be  recognized,  of  course,  that  fruits 
and  vegetables  are  healthful  foods,  and  are  an  essential  part 
of  well-regulated  dietaries,  but  it  is  well  for  those  who 
must  economize  to  know  that  they  are  comparatively  costly 
fuel.  As  their  use  safeguards  health,  they  have  a  value 
not  accounted  for  on  the  fuel  basis.  (The  costly  animal 
foods  are  fish  and  shellfish.  The  common  meats  like 
beefsteak  of  various  kinds,  lamb  chops,  and  beef  and  lamb 
roasts  occupy  a  middle  ground  among  animal  foods  as  to 
expensiveness,  not  differing  greatly  from  eggs  and  poultry. 
The  table  shows  clearly  that  the  cheapest  diet  is  the  one 
into  which  cereal  grain  foods  enter  most  largely,  also  that 
the  cost  of  living  is  increased  when  fish,  shellfish,  and 
chicken  broilers  take  the  place  of  dairy  products  and  the 
ordinary  meats.  In  the  matter  of  economy  the  vegetarian 
who  makes  a  free  use  of  cereal  products  has  a  great  ad- 
vantage over  the  meat  eater,  but  whether  he  has  other 
advantages  will  be  discussed  elsewhere.  Fruits,  however 
healthful  they  may  be,  excepting  possibly  grapes  and 
plums,  furnish  comparatively  high  cost  nutrition.  Of 
course  prices  are  not  fixed,  and  as  they  change  the 
relative  expensiveness  of  foods  changes. 


Cheap  and  Costly  Meals  231 

One  or  two  points  are  worthy  of  special  notice.  From 
the  standpoint  of  food  value,  white  bread  is  more  than  twice 
as  costly  as  the  wheat  flour  that  is  used  to  make  it.  A 
barrel  of  flour,  196  pounds,  will  make  on  the  average  about 
315  five-cent  loaves  of  bread.  The  bread  costs  the  con- 
sumer $15.75,  whereas  the  flour  can  be  bought  at  the  time 
of  writing  for  $6.50.  For  some  years  the  sale  of  skimmed 
milk  has  been  prohibited  in  the  city  of  New  York.  When 
sold  at  two  cents  per  quart,  it  supplies  nutrients  twice  as 
cheaply  as  whole  milk  at  six  cents  per  quart. 

Notable  examples  of  luxurious  living  are  the  payment 
of  $.50  to  $.75  per  pound  for  butter  of  an  especially  high 
flavor  when  good  creamery  butter  may  be  bought  for 
$.30  or  $.35,  the  purchase  at  high  prices  of  the  first  fruits 
and  vegetables  that  come  into  the  spring  market,  or  the 
purchase  of  anything  at  an  unusual  price  simply  because 
it  excels  in  flavor  or  appearance.  Such  expenditures  mean 
the  payment  of  a  heavy  tribute  to  appetite.  Exquisite 
flavor  may  serve  to  excite  a  desire  for  food,  may  even  over- 
stimulate  appetite,  but  only  to  that  extent  is  it  a  nutritive 
asset. 

223.  Cheap  and  costly  meals.  —  There  has  previously 
been  given  (see  p.  209)  examples  of  food  combinations 
that  were  presented  as  types  of  an  efficient  and  economical 
diet.  The  meals  suggested  are  simple  according  to  pres- 
ent standards  of  living  but  are  much  more  elaborate  than 
the  diet  upon  which  countless  numbers  of  men  and  women 
have  been  well  nourished.  The  table  which  follows  gives 
the  quantities  of  raw  materials  which  these  menus  would 
require  to  feed  a  family  of  six  persons  for  one  day,  and  there 
is  also  shown  the  actual  nutriment  supplied  with  its  cost :  — 


232 


Principles  of  Human  Nutrition 


TABLE    XXXVII 

No.  1 

A  DAY'S  SUPPLY  OF  FOOD  FOR  A  FAMILY  OF  Six  PERSONS 
(See  menu,  p.  208) 


MATERIALS 

PROTEIN 

FAT 

CARBO- 
HYDRATES 

COST 

Oz. 

4  Rolled  oats    
8  Flour  (Graham)      .... 
8  Flour  (white)      

Oz. 

0.64 
1.06 
0.89 

Oz. 

0.29 
0.176 
0.08 

Oz. 

2.70 
5.71 
6.00 

$0.025 
0.017 
0017 

40  Lean  mutton 

572 

524 

0250 

34  Milk 

1  12 

1  36 

1  70 

0080 

12  Butter 

0  16 

10  20 

0  240 

48  Potatoes 

0864 

0048 

706 

0060 

4  Rice      

0.32 

0.012 

3.16 

0025 

4  Macaroni       

0.536 

0.036 

2.96 

0.040 

1.036 

1.348 

0.01 

0.050 

8  Sugar 

0  50 

0030 

0880 

0  680 

5  69 

0055 

40  Bread   

3.68 

0.520 

21.23 

0.120 

4.1   P'nrlfioTi 

i   in 

o  019 

n  ft/to 

16  Peas      
Tea 

3.94 

0.160 

9.92 

0.075 
0005 

Coffee  

0.010 

20.86 

QQ    C 

20.16 

QQ  O 

66.14 

019  r 

$1.14 

oc7n 

.4O/U 

am  IQ 

Cheap  and  Costly  Meals 


233 


No.  2 

A  DAY'S  SUPPLY  OF  FOOD  FOR  A  FAMILY  OF  Six  PERSONS 
(See  menu,  p.  209) 


MATERIALS 

PROTEIN 

FATS 

CARBO- 
HYDRATES 

COST 

Oz. 

40  Corned  beef 

Oz. 

6  19 

Oz. 
9  52 

Oz. 

SO  30 

32  Flour    .     .               .          .     . 

358 

032 

2400 

0068 

32  Potato 

0  57 

4  74 

004 

8  Lima  beans 

1  45 

0  12 

527 

005 

64  Skimmed  milk                    i 

2.18 

049 

3  26 

008 

12  Eggs 

1.43 

1.12 

0.16 

32  Bread   ... 

294 

042 

1700 

008 

8  Butter 

6  80 

0  15 

5  2  Cheese 

1  38 

1  79 

006 

8  Sugar    

8.00 

0.005 

Grams  per  person  .... 

19.72 

98.18 

25.58 
97.2 

62.27 
294.2 

$0.993 

9400 

Calories  per  person 

«n  IACC 

The  above  are  examples  of  materials  sufficient  for  eight- 
een meals  for  one  person  that  are  simple  in  character,  easy 
to  prepare,  nutritious  and  inexpensive.  Such  a  diet  would 
support  an  average-sized  person  at  moderate  labor  and  is 
greatly  abundant  for  professional  men  or  those  doing  office 
work.  Many  similar  food  combinations  could  be  arranged, 
equally  nutritious  and  economical. 

It  is  possible  to  criticize  the  food  supply  in  these  two 
menus  on  the  ground  that  it  lacks  both  fruit  and  succulent 
vegetables.  While  the  healthfulness  of  fresh  fruit  and 
vegetables  must  be  conceded,  and  when  the  family  means 
justify  it,  they  should  be  included  in  the  dietetic  scheme,  it 


234  Principles  of  Human  Nutrition 

is  also  indisputable  that  they  do  not  furnish  economical 
nutrition.  Limited  means  predicate  their  limited  use,  es- 
pecially when  they  must  be  bought  in  a  city  market. 
'  In .  contrast  to  the  foregoing  examples  of  simple  and 
inexpensive  diet  are  the  two  following  dinner  menus,  one 
of  which  is  much  more  elaborate  than  the  other :  — 

Dinner  No.  1  Dinner  No.  2 

Oysters  on  half -shell  Clear  soup 

Clear  soup  Baked  bluefish 

Broiled  chicken  Mashed  potatoes 

Mashed  potatoes          Turnip  Cucumber  and  tomato  salad 
Celery              Cranberry  jelly  Saltines 

Lettuce  salad  Sliced  fruit  Cookies 

Saltines  Coffee 

Chocolate  ice  cream 

Cake  Coffee 

Cheese  Crackers 

Salted  nuts. 

It  is  estimated  by  an  experienced  dietitian  that  approx- 
imately the  following  supply  of  raw  materials  would  be 
needed  for  the  two  dinners,  the  cost  of  which  is  given  in 
Table  XXXVIII.  Reference  to  Table  XXXVI  shows 
that  these  dinners  are  made  up  of  raw  materials  that  in 
most  instances  are  costly  in  proportion  to  the  nutriment 
they  supply.  In  addition  to  this  the  number  of  courses, 
especially  in  No.  1,  requires  a  great  variety  of  raw  ma- 
terials, and  the  labor  of  preparation  and  serving  is  cor- 
respondingly large.  Such  meals  are  consistent  only  with 
the  possession  of  generous  means,  unless  the  expenditures 
of  the  family  are  to  be  unwisely  distributed  among  its 
real  needs. 


Two  Dinners  Compared 


235 


TABLE    XXXVIII 

Two  DINNERS  COMPARED 


Dinner  No.  2 
for  Six  Persons 


COST 


MATERIALS 


Dinner  No.  1 
for  Six  Persons 
MATERIALS 
18  Oysters       .     .     .     . 

1  Ib.  Beef  shank  .     .     . 

Seasoning 

3  Eggs  ...... 

12  Crackers,  saltines    . 
4|  Ib.  Chicken    .     .     . 

2  Ib.  Potatoes     .     .     . 
2  Ib.  Turnip   .... 
1  bunch  Celery   .     .     . 
1  pint  Cranberries  . 

1  head  Lettuce    .     .     . 

1  qt.  Thin  Cream    .     . 
|  Ib.  Chocolate    .     .     . 

2  Ib.  Sugar      .... 

2  Ib.  Salt  (Freezing)     . 
I  Ib.  Coffee     .... 
i  Ib.  Cheese    .... 

1  Ib.  Nuts 

£  Ib.  Flour      .... 
Baking  powder    .     .     . 

3  oz.  Salad  oil     ... 

2  oz.  Vinegar  .... 
f  Ib.  Butter    .... 
\  Ib.  Bread      .... 


Cost  per  person  . 

It  seems  that,  for  dinner  No.  1,  it  would  take  twenty-six 
kinds  of  raw  material,  and  for  dinner  No.  2,  eighteen  kinds. 

The  cost  per  person  for  the  raw  materials  of  dinner  No.  1 
would  be  $  0.58  and  for  dinner  No.  2  $0.305.  The  one  meal 
is  nearly  twice  as  expensive  as  the  other,  not  reckoning 


$0.30 

1 

Ib.  Beef  shank 

0.15 

Seasoning      .     .     .     . 

0.05 

2 

Eggs      

0.06 

4 

Ib.  BlueCsh     .     .     . 

0.03 

2. 

\  Ib.  Potatoes  .     .     . 

1.35 

2 

Cucumbers      .     .     . 

0.04 

3 

Tomatoes  .     .     .     . 

0.04 

1 

head  Lettuce  .     .     . 

0.10 

i 

Ib.  Malagas     .     .     . 

0.05 

3 

Oranges      .     .     .     . 

0.10 

i 

4 

Ib.  Coffee   .     .     .     . 

0.30 

1 

Ib.  Butter  .     .     .     . 

0.05 

Ib.  Bread    .     .     .     . 

0.12 

I 

Ib.  Sugar    .     .     .     . 

0.04 

i 

Ib.  Flour     .     .     .     . 

0.08 

1 

4 

Ib.  Cream  .     .     .     . 

0.05 

12  Saltines     .     .     .     . 

0.10 

0.017 

Cost  per  person      .     . 

0.01 

0.09 

0.02 

0.24 

0.015 

$3.402 

0.58 

COST 
$0.15 
0.05 
0.04 
0.72 
0.05 
0.10 
0.06 
0.05 
0.10 
0.10 
0.08 
0.16 
0.03 
0.045 
0.017 
0.05 
0.03 
$1.832 
0.305 


236  Principles  of  Human  Nutrition 

the  extra  labor  of  preparing.  The  contrast  with  two  days' 
simple  diet  previously  given,  where  cost  of  the  raw  materials 
per  person  for  one  day  was  $0.17  and  $0.19,  is  still  more 
marked,  with  no  disadvantage  in  the  simple  fare  as  to 
nutritive  efficiency  and  a  probable  advantage  as  to  health. 
224.  Rational  food  selection.  —  Several  objections  may 
be  raised  to  gauging  the  values  of  human  food  by  the  num- 
ber of  calories  bought  for  one  dollar.  In  the  first  place, 
it  may  be  said  that  the  edible  solids  of  one  food  are  greatly 
unlike  those  of  another  food  and  may  be  more  important 
in  the  animal  economy,  as,  for  instance,  beefsteak  has  more 
protein  than  wheat  flour,  and  will  go  farther  in  sustaining 
tissue  growth  or  repairing  tissue  waste.  This  is  grantee^ 
but  it  is  still  held  that  cheese  or  milk  is  a  cheaper  source  of/ 
protein  than  fresh  fish,  oysters,  lobster,  or  broiler  chickens,; 
and  that  the  necessary  protein  supply  may  be  selected  with 
reference  to  economy.  It  may  be  urged  with  truth,  too, 
that  with  adults  food  is  very  largely  used  to  furnish  energy, 
and  may  consist  chiefly  of  non-nitrogenous  materials,  and 
that  energy  from  wheat  flour  is  as  efficient,  if  not  more  so, 
and  costs  greatly  less,  when  it  comes  from  this  source  rather 
than  from  lake  trout  or  green  string  beans.  Other  objec- 
tions to  these  mathematical  measurements  of  food  values 
are  that  we  should  not  be  confined  to  a  few  articles  of  diet 
simply  because  they  are  cheap,  that  we  should  consider 
the  enjoyment  of  eating  as  well  as  the  economy,  that 
individual  tastes  differ,  that  some  persons  cannot  digest 
certain  foods  with  comfort,  and  that  health  demands  a 
variety  in  the  diet,  including  vegetables  and  fruit  which 
are  comparatively  costly.  These  are  facts  that  should  be 
admitted,  but  they  are  not  necessarily  obstacles  to  the 


Factors  in  Cost  of  Living  237 

practice  of  economy  in  selecting  food.  There  is  a  sufficient 
variety  of  the  desirable  and  less  costly  materials  to  satisfy 
fully  the  demands  of  a  normal  appetite,  individual  idiosyn- 
crasies, or  the  requirements  of  good  health.  Moreover, 
it  is  not  rational  for  families  of  moderate  means  to  indulge 
in  table  luxuries  on  a  par  with  rich  dress  fabrics,  Turkish 
rugs,  or  expensive  furniture.  Good  judgment  calls  for 
restraint  of  table  indulgence  as  much  as  of  the  desire  for 
social  display. 

It  is  admitted  that  a  variety  of  food  is  essential  to  the 
best  dietetic  results,  and  that  the  table  cannot  be  wholly 
supplied  with  the  cheaper  materials.  It  is  necessary  to 
use  some  foods  that  are  comparatively  costly.  This  does 
not  annul  the  fact,  however,  that  the  palatableness  and 
nutritive  effectiveness  t  of  two  dietaries  may  be  entirely 
out  of  proportion  to  their  cost,  due  wholly  to  a  wiser  selec- 
tion of  raw  materials  in  one  case  than  in  the  other.  At  the 
game  time,  the  writer  disclaims  any  sympathy  with  those 
extremists  who  point  out  the  low  relative  cost  of  cuts  of 
beef  from  the  neck  of  the  carcass  as  showing  how  cheaply 
a  family  may  secure  a  meat  supply,  or  who  set  forth  dietary 
plans  based  wholly  on  the  cheapest  materials  that  can  be 
selected.  These  devices  are  consistent  with  poverty,  but 
do  not  meet  the  real  needs  of  fairly  well-to-do  families. 

B.    OTHER  FACTORS  IN  THE  HIGH  COST  OF  LIVING 

There  come  every  now  and  then  periods  of  popular  dis- 
cussion and  even  extensive  complaint  over  what  is  believed 
to  be  the  excessive  cost  of  food  products.  Various  causes 
are  suggested  as  the  real  explanation  of  what,  for  a  time 
at  least,  is  regarded  as  an  oppressive  condition.  Tariff 


238  Principles  of  Human  Nutrition 

laws,  trusts,  excessive  profits  to  transportation  companies 
and  the  retail  trade  are  all  points  of  attack  by  those  who 
seek  to  place  the  responsibility  entirely  outside  of  the  busi- 
ness and  domestic  management  of  the  consumer.  These 
complaints  come  largely  from  those  families  that  are  sup- 
ported by  daily  wages  earned  in  manufacturing  and  com- 
mercial establishments.  It  is  often  asserted  by  these  wage 
earners  that  their  compensation  is  insufficient  to  meet 
reasonable  living  expenses.  Whatever  may  be  the  facts  as 
to  this  claim,  a  generous  share  of  the  cost  of  food  is  due  to 
factors  for  which  the  family  is  itself  responsible.  It  is 
fully  as  important  for  families  of  moderate  means  to  under- 
stand how  to  expend  money  for  life's  necessities  as  to  be 
able  to  increase  their  earnings.  The  relation  of  the  cost 
of  foods  to  their  nutritive  value  has  been  discussed  else- 
where (pp.  226-231).  There  is  much  unwise  buying  of 
foods  that,  nutritively  speaking,  are  very  expensive,  as  has 
been  shown. 

225.  Cost  of  distribution  of  foods.  —  Another  considera- 
tion of  importance  is  what  may  be  called  the  business 
management  of  the  food  supply.  The  cost  of  prepared 
food  as  it  reaches  the  table  includes  two  general  items : 
viz.,  the  money  paid  for  the  raw  materials  and  the  valueN 
of  the  time  and  fuel  used  in  preparing  and  cooking  themj 
Raw  food  materials  may  be  purchased  in  two  general  ways : 
in  supplies  sufficient  for  weeks  or  months,  or  in  daily  or 
Weekly  small  quantities.  The  latter  method,  which  is 
the  one  generally  adopted,  and  perhaps  necessarily  by 
some  families,  imposes  upon  the  consumer  a  heavy  expense 
for  distribution.  The  cost  to  the  groceryman  for  deliver- 
ing potatoes  and  apples  by  the  four  quarts  or  peck,  beets 


Cost  of  Distributing  Foods 


239 


by  the  dozen,  cabbages  by  the  head,  flour  and  sugar  in 
lots  of  a  few  pounds,  is  heavy,  and  the  consumer  pays  the 
bill. 

In  his  report  for  1910  the  Secretary  of  Agriculture  says 
that  "  the  distribution  of  farm  products  from  the  farm  to 
the  consumer  is  elaborately  organized,  considerably  in- 
volved and  complicated,  and  burdened  with  costly  fea- 
tures." On  the  basis  of  elaborate  inquiry  by  his  Depart- 
ment and  by  the  Industrial  Commission,  the  following 
increases  in  prices  from  the  producer  to  the  consumer  were 
found  to  exist :  — 

TABLE    XXXIX 

COST  OF  DISTRIBUTING  FOOD  PRODUCTS  TO  THE  CONSUMER 


PAID  THE 
PRODUCER 

PAID  BY  THE  CONSUMER 

Apples      

100 

190.5  by  barrel 

Beef  l 

100 

1380 

Butter                      

100 

115.8  prints 

Cabbage   

100 

235.3  by  head 

Milk 

100 

200  8  by  quart 

Onions       

100 

183.4  by  pound 

100 

500.4  by  dozen 

Potatoes 

100 

180.5  by  bushel 

Poultry     

100 

188.8  by  pound 

Apples        Cattle       Butter       Grains       Milk     Potatoes 

Freight  charges2      .13.6%     2.5%      .9%      7.7%     18%     14.8% 

It  is  clear  that  there  is  a  good  opportunity  through  the 
application  of  good  business  methods  to  lessen  these 
differences. 

1  Price  paid  slaughter  houses.  2  Per  cent  of  price  paid  producer. 


240  Principles  of  Human  Nutrition 

226.  Economy  in   buying  food.  —  A   large  proportion 
of  homes  have  storage  space  where  it  is  possible  to  hold 
flour,   sugar,   vegetables,   and  fruits  in  good  condition. 
When  this  is  the  case,  the  families  of  large  villages  and  small 
cities,  even  of  large  cities,  may  safely  arrange  to  buy 
directly  from  the  producer  in  barrel  or  bushel  lots  a  winter's 
supply  of  potatoes,  apples,  beets,  carrots,  and  turnips. 
Flour  may  be  bought  by  the  barrel.     Canned  goods  are 
cheaper  by  the  case  than  when  sold  in  single  packages. 
Certain  perishable  articles  like  milk  are  necessarily  taken 
in  daily  supply.     Where  refrigerator  space  is  available,  a 
two  weeks'  supply  of  butter  will  keep  in  good  condition. 
Several  families  might  unite  to  great  advantage  in  buying 
supplies.     No  money  can  be  invested  at  a  higher  rate  of 
interest  than  purchasing  certain  food  materials  in  consid- 
erable bulk. 

227.  Outside  preparation  expensive.  —  Again,  the  cash 
expense  of  supporting  a  family  is  greatly  increased  through 
the  transfer  to  outside  hands  of  much  of  the  cooking  that 
was  formerly  done  in  the  home.     Breakfast  foods  ready 
for  the  table  instead  of  the  cheaper  corn  meal,  oatmeal,  and 
hominy,  that  were  cooked  at  home,  bread,  cake,  and  other 
pastry  at  more  than  twice  the  cost  of  the  raw  materials, 
prepared  meats  and  other  articles  requiring  the  minimum 
of  home  labor,  greatly  increase  the  cash  expense.     It  may 
be  argued  that  cooked  food  is  cheaper  than  hired  help 
and  is  even  a  necessity  where  help  cannot  be  obtained. 
Certainly  the  groceryman  and  the  baker  contribute  to  the 
ease  and  comfort  of  housekeeping,  but  these  purveyors 
of  prepared  food  must  be  paid  for  their  services,  and  heavy 
cash  payments  are  in  this  way  substituted  for  home  labor. 


Cost  of  Preparing  and  Serving  Food          241 

Many  families  do  not  realize  how  much  is  paid  for  the  dis- 
tribution and  preparation  of  food  before  it  comes  into 
the  house.  One  remedy  is  to  buy  more  largely  from  the 
producer.  It  cannot  justly  be  claimed  that  the  prices 
he  now  receives  yield  him  an  undue  profit.  The  other 
remedy  is  home  preparation  of  food,  when  this  is  reasonably 
possible. 

C.  THE  COST  OF  PREPARING  AND  SERVING  FOOD 

228.  Elaborate   meals   burdensome.  —  All    housewives 
recognize  that  cooking  and  serving  three  meals  a  day,  with 
the  accompanying  dish  washing,  is  a  heavy  household  bur- 
den.    In  the  homes  of  the  wealthy  where  elaborate  menus 
of  several  courses  are  served,  for  luncheon  and  dinner  at 
least,  additional  service  is  a  necessity,  and  the  attendant 
expense  is  large,  to  say  nothing  of  the  increase  of  troubles 
and  perplexities  that  surround  the  servant  problem.     In 
the  homes  of  working  people,  where  the  limited  income 
will  not  permit  hired  help,  the  wife  and  mother  often 
regards  it  as  necessary  to  spend  many  weary  hours  in 
cooking  and  serving  a  great  variety  of  dishes,  especially 
cakes,  pies,  and  puddings. 

229.  A  simple  diet  abundantly  nutritious.  —  It  is  not 
claimed,  and  it  is  not  true,  that  the  nutritive  value  of  a 
given  amount  of  food  materials  is  increased  by  serving 
them  in  a  great  variety  of  forms.     This  is  done  merely  to 
offer  to  the  sense  of  taste  preparations  that  are  delectable. 
It  cannot  reasonably  be  claimed,  either,  that  beyond  a 
certain  limit  the  purchase  of  many  kinds  of  raw  food 
materials  promotes  nutritive  efficiency.     A  simple  diet 
involving  a  minimum  of  time  and  expense  for  preparation 


242  Principles  of  Human  Nutrition 

and  serving  may  be  just  as  nutritious  as  a  complex  one,  and 
is  likely  to  be  more  healthful  (see  pp.  231-236).  A  noon 
lunch  of  a  rich  vegetable  soup  containing  milk  or  meat 
products,  with  bread,  butter,  and  fruit  is  abundantly 
nutritious  and  much  less  expensive  than  a  series  of  dishes 
beginning  with  bouillon  and  ending  with  pastry  and  other 
delicacies.  The  writer  recalls  a  luncheon  in  the  home  of  a 
gentleman  of  wealth  and  prominence  that  consisted  solely 
of  a  large  peach  pudding,  with  cream.  A  dinner  of  a 
meat  course,  not  over  one  vegetable,  possibly  a  salad, 
potatoes,  bread  and  butter,  and  a  simple  dessert,  meets  all 
the  requirements  of  health  and  imposes  much  less  burden 
on  the  family  than  a  meal  with  the  approved  sequence 
of  courses.  Indeed,  the  usual  dessert  could  be  omitted 
with  no  loss  to  the  physical  welfare  of  the  family,  for  des- 
serts are  dictated  by  habit  rather  than  by  physiological 
demands.  As  a  matter  of  fact,  breakfasts,  luncheons,  and 
suppers  often  may  advantageously  consist  of  not  over 
two  or  three  articles  of  food. 

230.  Examples  of  simple  living.  —  Examples  may  be 
cited  in  great  number  where,  in  newly  settled  countries, 
the  kinds  of  raw  food  materials  being  very  limited  in  num- 
ber, families  have  been  well  nourished  and  children  have 
developed  into  fine  physical  types  of  men  and  women. 
It  is  known  on  good  authority  that  in  the  early  days  a 
New  England  family,  whose  children  became  men  and 
women  of  long  lives  and  great  endurance,  was  limited 
many  times  during  the  winter  months  to  as  few  foods  as 
bean  samp,  corn  bread,  and  salt  pork.  Such  narrow 
limitations  may  not  be  wholly  desirable,  but  they  show  the 
possibilities  of  a  simple  diet.  Wood  choppers  and  river 


Food  and  Social  Welfare  243 

drivers  have  endured  severe  labor  from  October  1  to  May  1 
chiefly  on  baked  beans  and  flour  biscuit,  the  beans  carry- 
ing a  generous  proportion  of  fat  from  salt  pork.  When  it 
is  possible  for  one  or  two  articles  of  diet  to  supply  the  nutri- 
ents essential  to  the  needs  of  the  human  body,  it  is  not  neces- 
sary to  add  others,  excepting  as  a  variety  of  food  promotes 
a  continuance  of  good  appetite.  The  apparent  demand  for 
an  elaborate  diet  is  the  result  of  education,  and  if  simpler 
living  were  the  fashion,  there  would  be  no  loss  of  good 
appetite,  and  there  would  be  a  certain  decrease  in  household 
expenses  with  a  probable  gain  in  good  health.  It  is  un- 
fortunate, to  say  the  least,  that  with  so  many  opportu- 
nities for  useful  activity  and  real  enjoyment,  the  lives  of 
men  and  women  should  be  burdened  with  the  unnecessary 
labor  caused  by  irrational  dietetic  habits. 

D.  THE  RELATION  OF  FOOD  ECONOMICS  TO  SOCIAL 
WELFARE 

The  continued  existence  of  a  strong  and  highly  civilized 
people  is  insured  only  when  certain  fundamental  condi- 
tions prevail.  A  virile  nation  is  one  whose  citizens  are  of 
a  good  physical  type,  which  means  that  they  are  well 
nourished.  A  well-fed  people,  other  conditions  being 
favorable,  is  a  strong  people.  Food  is  the  physical  basis, 
not  only  of  individual  activity,  but  also  of  social  energy. 
Any  causes,  therefore,  which  limit  the  food  supply  or  in- 
crease the  burden  of  securing  adequate  nourishment 
strike  a  blow  at  a  nation's  vital  powers.  It  is  for  these 
reasons  that  thoughtful  men  are  solicitous  concerning  the 
conservation  of  the  fertility  of  our  soil.  By  just  so  much 


244  Principles  of  Human  Nutrition 

as  the  crop-producing  capacity  of  this  nation  is  diminished 
will  its  endurance  and  power  be  lessened.  But  the  con- 
servation of  the  food  supply  involves,  not  only  the  preserva- 
tion of  the  means  of  producing  it,  but  also  the  economical 
use  of  that  which  is  produced. 

231.  Enormous  food   waste.  —  In  recent  times  there 
has  been  a  widespread  discussion  over  the  cost  of  living, 
and  many  have  attributed  the  advance  in  the  prices  of 
food  materials  to  their  wasteful  use.     While  doubtless 
several  factors  are  involved  in  the  situation,  the  enormous 
waste  of  food  in  the  United  States  is  not  to  be  doubted. 
This   comes   about   through   careless   servants,    ignorant 
methods  of  preparation  in  the  family  kitchen,  unskillful 
cooking,  and  especially  from  the  very  large  proportion  of 
refuse,  originating  in  high-class  raw  material,  that  goes 
out  from  boarding  houses  and  hotels.     It  is  probably  not 
an  exaggeration  to  claim  that  the  people  of  this  nation 
waste  enough  raw  food  materials  to  properly  feed  half 
their  number.     If  our  raw  foods  were  economically  utilized 
and  this  waste  was  stopped,  we  could  export  more  wheat 
and  meat  or  other  products,  and  the  means  saved  could  be 
turned  to  useful  ends. 

232.  Expensive    service    and    equipment.  —  Moreover, 
a  generous  part  of  our  population  lives  under  certain  con- 
ditions at  an  expense  that  is  a  great  drain  upon  individual 
and  social  energy.     A  simple  breakfast,  at  a  high-class 
hotel,  of  fruit,  cereal,  eggs,  potato,  and  bread  and  butter, 
together  with  a  ten-cent  fee  to  the  waiter,  costs  the  par- 
taker not  less  than  $1.25,  —  a  sum  that  would  pay  family 
board  for  five  meals,  or  would  buy  the  raw  material  neces- 
sary to  feed  one  person  for  at  least  three  days.     The  price 


Food  and  Social  Welfare  245 

of  this  hotel  meal  is  made  up  only  in  small  part  of  the  cost 
of  the  raw  food  materials,  but  comes  largely  from  the 
absorption  of  capital  in  an  expensive  building  and  in  elab- 
orate equipment  and  service.  The  habitues  of  hotel 
tables  pay  more  for  their  environment  and  manner  of  life 
than  they  do  for  what  they  eat.  Now,  if  our  living  was 
more  simple,  and  our  flour,  meats,  vegetables,  and  fruits 
were  used  with  maximum  economy,  the  saving  would  sup- 
port public  utilities,  extend  charities,  pay  the  national 
debt,  and  in  other  ways  contribute  to  the  higher  aims  of 
social  life,  besides  promoting  good  health.  In  fact,  the 
people  of  this  nation,  with  a  given  amount  of  energy  to 
apply  in  one  direction  or  another,  is  expending  an  undue 
proportion  of  its  activities  in  paying  for  expensively 
compounded  and  expensively  served  foods,  with  a  corre- 
sponding limitation  of  the  means  which  might  secure 
larger  individual  and  social  values. 


CHAPTER  XIII 
SPECIAL    DIETETIC   METHODS 

THERE  are  a  few  people  who  advocate,  and  claim  to 
follow,  special  dietetic  methods  such  as  vegetarianism  and 
uncooked  (raw)  foods.  The  advocates  of  these  dietetic 
practices,  which  are  followed  in  some  countries  at  least  by 
a  few  persons,  profess  to  find  in  scientific  facts  and  daily 
experience  a  justification  of  their  position.  It  appears 
to  the  writer  that  arguments  advanced  in  favor  of  these 
unusual  eating  habits  are  generally  presented  in  a  manner 
that  is  far  from  judicial.  Certain  well-established  facts 
are  assumed  to  support  the  contentions  made,  when  a 
connection  has  not  been  established  by  proof,  antagonistic 
facts  are  ignored,  and  the  long-continued  experience  of 
the  human  family  on  a  mixed  diet  of  cooked  meats  and 
vegetables  is  given  less  weight  than  it  deserves.  It  is  the 
method  of  argument  adopted  by  those  persons  who  have 
come  to  see  a  single  set  of  facts  in  exaggerated  perspective. 

A.  VEGETARIANISM 

/  Vegetarians  are  those  persons  who,  while  in  some  instances 
\  admitting  and  defending  the  use  of  eggs  and  milk,  hold,  in 
i theory  at  least,  that  the  eating  of  meats  is  deleterious  to 
\the  physical  welfare  of  the  human  family.  Their  position 
is  based  on  the  following  grounds :  — 

246 


Vegetarianism  247 

i  is  anatomically  not  a  carnivorous  animaj/ 

2.    Meat  is  an  unnecessary  article  of  diet. 

jJ^The  use  of  meat  is  a  menace  to  the  health  of  man 
mainly  for  the  following  reasons  :  — 

a  J/Lcauses  an  overconsumption  of  protein,  which  pro- 
motes certain  diseases. 

6  It  greatly  promotes  the  growth  of  bacteria  in  the 
intestinal  tract. 

c  It  is  a  fruitful  source  of  toxins  that  are  dangerous 
to  health  or  even  life. 

d  Vegetarians  are  healthier  and  have  greater  physical 
endurance  than  meat  eaters. 

233.  Anatomical  considerations.  —  Does  the  structure 
of  the  human  animal  indicate  that  he  should  not  eat  flesh  ? 
This  question  seems  somewhat  absurd  in  view  of  the  fact 
that  man  has  been  eating  flesh  for  centuries,  and  that  on  a 
partially  flesh  diet  men  of  great  vigor  and  endurance  have 
been  grown.  Facts  overshadow  theories.  The  earliest 
recorded  history  tells  us  of  flesh  eating.  In  a  savage  state 
man  eats  flesh  freely.  I^The  Norsemen,  the  mighty  men  of 
the  north,  were  flesh  eaters.)  To  be  sure,  man  has  not  now 
prehensile  teeth,  but  he  succeeds  fairly  well  in  masticating 
cooked  flesh.  It  is  not  surprising  that  in  view  of  his  in- 
telligent methods  of  securing  food,  other  means  than  teeth 
are  used  for  capturing  and  holding  his  prey.  So  far  as 
internal  structure  is  concerned,  the  length  of  man's  intes- 
tines is  shorter  than  that  of  animals  eating  no  meat,  and 
longer  than  that  of  carnivorous  animals,  —  a  fact  that  may 
have  little  significance,  however.  Anyway,  man  success- 
fully digests  meat. 

Vegetarians  can  find  little  in  man's  structure  to  support 


248  Principles  of  Human  Nutrition 

their  position,  so  far  as  we  can  discover.  Man  has  always 
eaten  flesh,  and  to  say  that  he  should  not,  because  of  his 
anatomical  structure,  is  not  a  convincing  reason  for  declar- 
ing that,  through  countless  generations,  man  has  failed  to 
discover  the  food  that  best  serves  his  bodily  needs,  and  for 
so  long  has  followed  abnormal  eating  habits.  This  would 
be  about  as  rational  as  to  declare  that  a  squirrel  should  not 
eat  nuts. 

234.  Is  flesh  protein  necessary  ?  —  One  of  the  main 
arguments  of  the  advocates  of  a  fleshless  diet  is  that  the 
physical  welfare  of  man  does  not  demand  meat  as  a  part 
of  his  food.  It  is  asserted,  and  with  truth,  that  human 
beings  have  been  grown  and  maintained  in  activity  on  a 
vegetable  diet.  Surely  this  can  be  done  if  milk  and  eggs^ 
are  admitted  to  be  "  vegetarian."  _j 

Apart  from  practical  experience,  it  is  now  very  evident^ 
from  our  knowledge  of  the  compounds  of  plants  and  from 
our  studies  of  metabolism,  that  a  vegetable  diet  can  and 
does  perform  the  complete  round  of  nutritive  functions^ 
The  larger  part  of  food  is  used  for  energy  production,  and 
no  source  of  energy  is  physiologically  more  efficient  than 
starch  and  its  allies.  The  proteins  of  plants  and  animals 
are  closely  alike  in  constitution,  if  we  may  judge  from 
their  cleavage  products,  and  certainly  perform  similar 
functions.  It  is  true,  however,  that  the  meat  proteins\ 
correspond  more  closely  to  the  constructive  demands  of  the  j 
human  body  than  do  the  plant  proteins,  and,  consequently,  j 
in  rearranging  the  "  building  stones  "  for  the  construction] 
of  animal  tissue,  it  seems  almost  certain  that  there  would 
be  less  waste  from  flesh  proteins  than  from  those  having 
a  vegetable  source.  But,  after  all,  the  protein  tissue  of 


Vegetarianism  249 

many  forms  of  brute  life  is  constructed  wholly  from  vege- 
table protein,  and  we  may  safely  reason  that  the  same  may 
occur  with  the  human  species. 

But  while  plant  and  flesh  proteins  are  on  a  par  as  to  kind 
of  functions,  is  a  purely  vegetable  diet  likely  to  supply 
protein  in  a  quantity  essential  to  the  most  effective  nutri- 
tive results,  unless  vegetable  foods  are  reenforced  by  milk 
and  eggs,  —  a  practice  which  some  vegetarians  (?)  admit 
to  be  good?  The  quantity  of  ingested  protein  that  a 
vegetarian  diet  supplies  is  generally  below  the  accepted 
dietary  standards.  Whether  or  not  this  minimum 
protein  diet  is  desirable,  is  discussed  elsewhere  in  this 
volume  (pp.  195-199). 

The  real  question  is  not  whether  flesh  proteins  are  a  nec- 
essary part  of  the  human  diet,  but  whether  meat  eating 
in  a  reasonable  way  is  harmful,  or  may  not  have  its 
advantages. 

235.  The  harmfulness  of  a  mixed  flesh  and  vegetable 
diet.  —  Vegetarians  allege  not  only  that  eating  flesh  is  not 
necessary,  but  that  it  is  harmful.  This  is  a  universal  con- 
demnation without  reference  to  the  extent  to  which  flesh 
foods  are  incorporated  in  the  diet,  whether  moderately  or 
in  excessive  proportions. 

The  main  grounds  on  which  flesh  eating  is  condemned 
are  the  following :  — 

\.  Intestinal  bacteria  are  thereby  greatly  increased. 
/2.  Certain  compounds  in  flesh*  are  the  progenitors  of 
uric  acid,  and  therefore  flesh  eating  tends  to  rheumatic 
trpubles. 

J3.  Cases  of  toxic  poisoning  are  caused  by  eating  flesh 
fobds  that  have  undergone  certain  fermentations. 


250  Principles  of  Human  Nutrition 

236.  Bacteria  in  foods.  —  Figures  are  given  in  the  argu- 
ments  for  vegetarianism   showing  that   uncooked    flesh 
carries  with  it  very  great  numbers  of  bacteria,  which  is 
undoubtedly  true,  although,  as  little  flesh  is  eaten  the  out- 
side of  which  is  not  cooked,  counts  of  surface  bacteria 
unduly   magnify   the   fact.     No   comparisons   are   made 
between  the  number  of  bacteria  conveyed  by  meat  and 
those  in  market  milk,  or  in   uncooked  vegetables  that 
have  been  exposed  in  the  markets,  neither  is  any  direct 
proof  furnished  that  the  meat  inhabiting  bacteria  are 
a  cause  of  intestinal  troubles  in  a  normal,  healthy  in- 
dividual. 

237.  Bacteria  abundant  in  intestines.  —  The  intestinal 
tract  of    man,  chiefly  the  colon  or  large  intestine,  nor- 
mally contains  countless  numbers  of   bacteria  that  are 
developed   mostly  in    the    intestine,  although    a    minor 
part  may  be  introduced  with  the  food. 

Competent  investigators  agree  that  quite  a  portion  of  the 
fecal  residue  consists  of  dead  or  living  bacteria  that  have 
accumulated  in  the  large  intestine,  but  it  is  not  affirmed 
that  this  fact  is  an  indication  of  harm.  Some  able  authori- 
ties hold  that  the  presence  of  these  organisms  is  essential 
to  digestion.  Their  action  on  proteins  is  in  some  respects 
similar  to  that  of  the  digestive  enzyms,  and  the  resulting 
products  may  have  the  same  value  to  the  body.  The 
digestion  of  cellulose  is  accomplished  wholly  by  bacteria, 
and  these  organisms  cause  acid  formation  from  carbohy- 
drates. Their  action  on  fats  is  regarded  as  slight. 

238.  Relation    of     foods    to    intestinal     bacteria.  — 1£) 
is  argued  that  flesh  foods  are  favorable  to  the  growth/ 
of  intestinal  bacteria.     They  are  present,  however,  in  the 


Vegetarianism  251 

large  intestines  in  very  great  numbers  with  any  diet. 
/The  fact  is,  vegetable  foods  are  known  to  be  very  favor- 
,'able  media  in  which  to  develop  micro-organisms,  as  is 
shown  in  laboratory  processes  and  in  the  rapid  fermenta- 
tions which  such  foods  undergo.  It  is  significant  that 
lerbivorous  animals  are  the  subjects  of  acute  intes- 
tinal fermentations.  Doubtless  the  nature  of  the 
diet  greatly  influences  the  type  of  bacteria  that  is 
dominant  in  the  intestinal  tract  at  any  given  time.  A 
heavy  meat  diet  would  favor  the  increase  of  the  putre- 
factive forms,  while  a  vegetable  diet  or  one  containing 
sugar,  or  sugar-forming  bodies,  would  favor  acid-producing 
forms.  No  proof  is  yet  forthcoming  that  a  reasonable 
mixed  diet  of  flesh  and  vegetables  is  any  more  dangerous 
to  health  through  the  kind  or  extent  of  bacterial  develop- 
ment than  is  a  purely  vegetable  diet.  Doubtless  heavy 
meat  eating,  especially  when  excretion  is  imperfect,  may 
result  in  toxic  disturbances  through  putrefactive  fermen- 
tations in  the  intestines,  but  while  "  auto  intoxication  " 
may  be  promoted  under  abnormal  conditions  by  an 
abundance  of  meat  proteins  in  the  intestinal  tract,  there 
is  no  evidence  that  reasonable  flesh  eating  is  more  danger- 
ous in  this  particular  than  a  vegetable  diet.  Inferential 
conclusions  based  on  bacterial  counts  are  not  safe.  That  is, 
it  is  not  proved  that,  under  normal  conditions,  a  possible  ex- 
cess of  intestinal  bacteria  with  a  mixed  diet  does  any  harm. 
It  seems  probable  that  the  acute  indigestions  sometimes 
attendant  upon  generous  consumption  of  vegetables,  fruits, 
and  various  "  sweets,"  and  which  may  be  due  to  bacterial 
action,  are  fully  as  serious  as  any  similar  disturbances  that 
may  be  caused  by  flesh  eating. 


252  Principles  of  Human  Nutrition 

239.  Flesh   foods   contain   uric   acid   formers.  —  Vege- 
^tarians  urge  that  flesh  should  be  excluded  from  the  diet  of 
!  man  because  such  foods  cause,  or  aggravate,  rheumatic 
Vtroubles.     Physicians  advise  their  patients  afflicted  with 
rheumatism  to  avoid  certain  meats  or  cut  down  to  a 
minimum  the  amount  eaten.     While  this  advice  is  often 
not  consistent  in  its  details,  the  reasons  lying  behind  it 
are  that  flesh,  and  especially  certain  glands  like  liver,  con- 
tain a  small  proportion  of  compounds  known  as  purins 
which  are  progenitors  of  uric  acid,  and  that  an  accumula- 
tion of  uric  acid  in  the  body  is  regarded  as  the  exciting 
cause  of  various  forms  of  rheumatism.     Vegetable  foods, 
milk  products,  and  eggs  are  allowed  on  the  ground  that, 
with  such  a  diet,  the  minimum  of  uric  acid  is  formed.     As 
a  matter  of  fact,  it  has  been  shown  that  the  addition  of 
flesh  to  a  vegetable  diet  increases  the  output  of  uric  acid, 
and  it  is  rational  that  persons  with  a  uric  acid  diathesis 
(tendency)  should  eat  flesh  sparingly,  including  the  flesh 
of  fish,  or  not  at  all. 

240.  Purins  in  vegetable  foods.  —  At  the  same  time, 
it  is  not  yet  fully  determined  whether  uric  acid  may  not 
result  from  synthesis  in  the  human  body,  besides  which 
vegetable  foods  are  not  free  from  purins,  as  the  following 
table  shows. 

These  figures  make  it  evident  that  even  on  a  vegetable 
diet,  uric  acid  forming  compounds  are  not  escaped,  only 
minimized.  It  is  a  question,  too,  whether  rheumatism  is 
not  promoted  fully  as  much  by  habits  of  life  as  by  special 
articles  of  diet.  It  is  certain  that  the  great  majority  of 
persons  who  do  not  abuse  themselves  with  overindulgence 
in  eating  or  drinking,  who  take  sufficient  exercise  and  who 


Vegetarianism 


253 


TABLE    XL 
THE  PTJRIN  CONTENT  OP  CERTAIN  FOODS  1 


GRAMS  PER 
KILOGRAM 

GRAMS  PER 
KILOGRAM 

Fish 

Cod 

050 

Special  foods 

Milk 

Salmon      .... 
Halibut 

1.10 
1  00 

Butter    .... 

"R  trprg 



PVmo«« 

Meats 

Beef     
Mutton     .... 
Veal 

1.10  to  2.00 
0.96 
1  10 

Beverages 

Lager  beer  .     .     . 
Ale     

0.12 
0.14 

Pork  (lean)    .     .     . 
Ham          .... 

1.20 
1.10 

Porter     .... 
Tea  (per  cup)  . 

0.15 
1.20 

Chicken    .... 

Vegetables 

Potatoes   .... 
"Ripft 

1.20 
0.02 

Cocoa     .... 
Chocolate    .     .     . 
Coffee     .... 
Claret     .... 

1.00 
0.70 
1.70 

Tfloiir 

Sherry     .... 

"Dfoarl 

Brandy  .... 

Oat  meal  .... 
Peas          .          . 

0.53 
0.39 

Lentils      .... 

0.38 
0.63 

Asparagus 
Cabbage    .... 

0.21 

Lettuce     .... 

do  not  submit  themselves  to  extreme  conditions  of  inac- 
tivity or  exposure,  generally  are  not  afflicted  with  rheu- 
matic troubles,  even  if  generous  meat  eaters.  Persons  with 

i  "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  Ill,  p. 
1297. 


254  Principles  of  Human  Nutrition 

a  pronounced  uric  acid  tendency  should  avoid  flesh  eating, 
perhaps,  just  as  some  persons  should  avoid  strawberries, 
£weets,  milk,  cheese,  cabbage,  or  some  other  food  that 
broves  to  be  harmful  because  of  constitutional  peculiari- 
pies.  It  does  not  follow  when  one  person  cannot  safely 
indulge  in  a  mixed  diet  of  flesh  and  vegetable  food  that 
every  one  else  should  exclude  the  flesh. 

241.  Danger  from  toxins.  —  It  is  pointed  out  that 
toxins  (poisons),  are  developed  in  meats  under  certain 
conditions,  the  effect  of  which  sometimes  menaces  human 
life.  Occasionally  cases  of  serious  illness,  sometimes! 
fatal,  are  reported  from  this  cause,  but  when  we  consider; 
the  immense  quantities  of  flesh  consumed  by  millions  of 
people,  such  occurrences  must  be  considered  as  infinitesimal  I 
in  their  proportions.  Ice  cream  poisoning,  probably  due 
to  badly  fermented  cream,  and  toxic  cheese,  the  condition 
of  which  is  not  at  present  fully  explained,  cause  illness  fully 
as  frequently  as  meat,  fish,  or  poultry.  It  is  safe  to  assert 
that  acute  indigestions  due  to  overeating  of  sweets,  unripe 
fruits  and  vegetables,  cause  fully  as  much  human  suffering 
and  as  many  deaths  as  do  unsound  flesh  foods.  It  is 
unfair  to  charge  against  any  class  of  foods  the  harm  which 
it  does  through  bad  conditions  of  holding  and  preparation, 
or  through  overindulgence  on  the  part  of  the  victim.  t 

In  normal  digestion,  it  cannot  be  maintained  on  any 
ground  whatever  that  the  resulting  products  from  flesh 
proteins  and  fats  differ  in  their  relations  to  good  health 
from  similar  compounds  that  the  digestive  enzyms  or 
the  intestinal  bacteria  produce  from  plant  substance. 
The  digestive  cleavage  products  of  animal  proteins  and 
plant  proteins  are  greatly  alike  in  kind,  though  differing 


Vegetarianism  255 

in  proportion,  and  there  is  not  the  slightest  evidence  that 
those  from  one  source  have  deleterious  physiological  reac- 
tions not  possessed  by  those  from  the  other  source.  What 
may  happen  with  overindulgence  with  any  class  of  foods 
is  not  to  the  point. 

242.  The  physical  quality  of  flesh  eaters  as  compared 
with  vegetarians.  —  Those  who  advocate  a  vegetable  diet, 
with  the  exclusion  of  flesh  products,  claim  that  persons 
grown  and  maintained  on  foods  of  plant  origin  have  greater 
physical  stamina  than  those  who  have  developed  and  sub- 
sist on  a  mixed  diet.  This  appears  to  be  an  unwarranted 
assumption.  In  the  first  place,  it  is  exceedingly  difficult 
to  produce  conclusive  proof  by  which  to  settle  this  ques- 
tion. A  comparison  of  the  endurance  of  a  few  individuals 
means  but  little,  because  it  is  almost  impossible  to  select 
persons  that  represent  the  average  of  a  race  or  a  type. 
Conclusions,  so  far  as  they  are  justified,  must  be  based 
on  racial  or  regional  data  where  it  is  possible  to  compare 
the  physical  quality  associated  with  characteristic  food 
supply. 

Certain  savage  tribes  exist  at  times  on  an  almost 
exclusive  meat  diet,  and  the  people  of  the  United  States, 
England,  and  European  states,  consume  immense  quan- 
tities of  flesh.  On  the  other  hand,  the  inhabitants 
of  China  and  Japan  are,  to  a  large  extent,  vegeta- 
rians. In  the  early  history  of  this  country,  especially  in 
the  day  of  buffalo  meat  on  the  Western  plains,  the  Indians, 
as  well  as  the  hardy  trappers  and  early  settlers,  subsisted 
at  times  on  a  very  heavy  flesh  diet.  This  has  been  true 
during  the  conquering  of  any  new  country  where  game  has 
been  a  prominent  article  of  food.  It  is  within  the  facts 


256  Principles  of  Human  Nutrition 

;o  say  that  men  and  women  of  splendid  physical  physique 
lave  been  produced  and  nourished  under  these  primitive 
iietetic  conditions,  and  it  is  equally  certain  that  the  meat- 
bating  people  have  produced  individual  types  of  men, 
especially  if  we  base  our  judgment  on  athletic  contests, 
than  which  there  have  been  no  finer  or  more  enduring. 
The  athletes  of  the  United  States  and  England  are  the  peers 
of  any.  It  is  fair  to  inquire,  too,  whether  the  small  stature 
of  the  Chinese  and  Japanese  is  not  related  in  some  meas- 
ure to  their  diet.  And  we  should  give  full  weight  to 
the  fact  that  the  Romance  peoples,  into  whose  diet  flesh 
enters  very  sparingly,  cannot  claim  physical  superiority. 
It  is  safe  to  assert  that  there  are  no  facts  or  principles  in 
nutrition,  and  no  large  experience  of  the  human  species, 
which  justify  the  assertion  that  reasonable  flesh  eating  is 
a  cause  of  inferior  physical  quality.  Physical  quality  is, 
of  course,  dependent  on  many  factors,  and,  to  analyze  these 
in  their  relation  to  an  individual  or  a  group  of  individuals 
and  assign  to  one  a  dominating  influence,  would  be  ex- 
tremely difficult,  if  not  impossible. 

243.  General  considerations  as  to  meat  eating.  —  The 
apostles  of  the  vegetarian  doctrine  are  rendering  a  useful 
service  in  calling  attention  to  the  abuses  of  flesh  eating. 
As  has  been  pointed  out,  meat  and  fish  are  by  far  the  most 
expensive  part  of  the  family  food  supply.  Many  families, 
even  those  of  moderate  means,  burden  their  resources  by 
the  purchase  of  flesh  food  to  an  extent  that  is  not  essen- 
tial to  the  very  best  dietetic  conditions.  The  common 
belief,  especially  among  laboring  people,  that  a  family  is 
not  well  fed  unless  meats  are  eaten  freely  three  times  a  day, 
is  a  tradition,  and  has  no  justification  in  fact.  The  energy 


Raw  Foods  257 

used  in  manual  labor  comes  very  largely  and  most  effi- 
ciently from  carbohydrates,  that  is,  from  the  grain  foods. 
Moreover,  the  excessive  use  of  meats  places  upon  the 
human  organism  unnecessary  burdens  and  promotes  any 
tendency  that  may  exist  towards  those  ailments  associated 
with  the  by-products  of  protein  metabolism.  Undoubt- 
edly, if  the  American  people  would  cut  down  its  consump- 
tion of  flesh  foods,  it  would  result  in  an  advantage  to  health 
and  would  lighten  the  cost  of  living.  On  the  other  hand, 
the  ease  and  completeness  with  which  meats  are  digested 
by  most  persons,  the  efficiency  for  constructive  purposes 
of  meat  proteins,  and  the  absence  of  any  conclusive  proof 
that  moderate  meat  eating  is  harmful,  are  good  arguments 
for  the  reasonable  use  of  meat  in  families  of  comfortable 
circumstances. 

B.    EATING  RAW  FOODS 

One  of  the  modern  food  fads  that  is  occasionally  advo- 
cated is  the  eating  of  all  foods  in  a  raw  condition.  The 
arguments  in  favor  of  this  practice  appear  to  be  based 
wholly  on  a  real  or  fancied  personal  experience;  indeed, 
this  must  be  so,  because  there  are  no  well-established 
scientific  facts  that  in  fairness  can  be  used  to  support  the 
claim  that  foods  in  a  raw  state  are,  in  general,  more  health- 
ful or  more  efficient  than  when  cooked. 

If  cooked  foods  are  inferior  to  raw  in  healthfulness  or 
efficiency,  the  explanation  must  lie  largely  in  one  or  more 
of  the  following  factors  :  — 

il  Poorer  mastication  of  the  cooked  food. 
j2  A  lower  ratio  of  digestibility. 

( 3  A  less  nutritive  efficiency  or  different  function  of  the 
food  compounds  in  a  cooked  state. 


258  Principles  of  Human  Nutrition 

244.  Mastication.  —  It  is  undoubtedly  true  that  much 
more  time  would  be  consumed  in  masticating  raw  cereals 
and   vegetables  than  is  required   after  these  foods   are 
cooked.     This  would  result  in  a  more  complete  admixture 
of  the  saliva  with  the  masticated  food.     It  is  probable, 
however,  that  the  uncooked  cereal,  being  much  harder  and 
more  tenacious  than  the  cooked,  would  not  be  reduced  to 
as  fine  a  mechanical  condition  as  after  being  disintegrated 
by  either  wet  or  dry  heat. 

245.  Digestibility.  —  In  any  case,  there  is  every  reason 
for  asserting  that  cooking  vegetable  foods  makes  possible 
a  prompter  and  more  complete  digestion  because  of  a  rup- 
ture of  the  cells  containing  the  effective  nutrients,  which  is 
certainly  a  desirable  result.     The  less  complete  the  diges- 
tion, the  larger  the  fecal  residue,  and,  for  this  reason,  un- 
cooked foods  may  possibly  have  some  advantage  for  per- 
sons to  whom  constipation  is  a  constant  menace,  although 
the  use  of  coarse  bread  containing  wheat  or  bran,  or  a  free 
use  of  fruit  and  vegetables,  is  probably  as  efficient  a  bowel 
regulator  as  any  uncooked  materials  could  possibly  be. 

246.  Influence  of  cooking  on  function.  —  No  advantage 
can  be  claimed  for  uncooked  foods  because  of  any  differ- 
ence in  function,  or  greater  efficiency,  of  raw  proteins  or 
carbohydrates  over  those  that  have  been  submitted  to 
heat,  excepting  that  cooked  animal  proteins  like  those  in 
meat  and  eggs  more  slowly  digest  after  coagulation,  but 
do  not  seem  to  be  less  completely  digested.     Function  is 
not  changed  by  cooking.     Raw  proteins  and  raw  starch 
when  digested  will  do  no  more  work,  or  no  different  work, 
in  the  animal  organism  than  coagulated  protein  or  hydro- 
lyzecl  starch.     A  real  disadvantage  attending  the  consump- 


Raw  Foods  259 

Ikion  of  raw  foods,  fruits  excepted,  is  the  absence  of  the 
(flavors  that  are  developed  by  cooking.  These  flavors  are 
a  real  nutritive  asset  as  excitants  of  the  secretion  of  the 
digestive  fluids.  On  the  whole,  the  proposition  to  eat  all 
foods  raw  is  not  only  irrational,  but  even  absurd,  when 
regarded  in  the  light  of  well-established  facts. 


CHAPTER  XIV 
THE   NUTRITION  OF   THE  CHILD 

THE  nutrition  of  the  child  is  a  matter  of  supreme  impor- 
tance to  the  physical  welfare  of  the  race.  It  is  during  the 
time  of  active  growth  that  the  physical  status  of  the  adult 
is  established,  and  the  errors  of  nutrition  committed  during 
this  period  are  likely  to  handicap  the  individual  during  his 
entire  life.  The  development  of  a  human  being  begins 
with  the  embryo  and  passes  in  succession  through  the 
fetal  stage,  the  infantile  period,  when,  under  natural 
conditions,  milk  is  the  only  food,  and  the  later  and  longer 
period  of  growth,  when  the  diet  is  similar  in  a  general  way 
to  that  of  adults.  No  one  of  these  periods  is  unimportant 
in  its  relation  to  the  ultimate  product,  —  the  full-grown 
man  or  woman. 

A.    THE  NOURISHMENT  OF  THE  FETUS 

247.  Growth  of  fetus.  —  The  growth  of  the  human 
young  begins  with  the  development  of  the  fertilized  ovum 
in  the  uterus.  During  the  succeeding  nine  months  of 
in  utero  existence,  the  embryo  and  fetus  increase  in  sub- 
stance by  the  deposition  of  compounds  the  same  in  kind 
as  those  which  are  applied  to  constructive  purposes  subse- 
quent to  birth.  The  following  analysis  of  the  human 

260 


Growth  of  Fetus 


261 


fetus  partially  developed,  and  at  time  of  birth,  illustrates 
the  truth  of  the  above  statement: — 

TABLE  XLI 

COMPOSITION  OF  THE  EMBRYO  AND  FULLY  GROWN  FETUS  * 


WEIGHT 

DRY 

SUBSTANCE 

NITROGEN 

FAT 

ASH 

Embryo  (7  months) 
Fully  grown  fetus    .     . 
Addition  in  about  100 
days  .                     .     > 

Grams 
900-1000 
3200 

2250 

Grams 
150-160 
850-1000 

700-850 

Grams 
16 
60-65 

45-50 

Grams 
26 
350 

350 

Grams 
26 
85-100 

60-75 

Average    addition    per 
day  last  100  days 

22.5 

7.0-8.5 

.45-.50 
3    grams 
albumin 

3.5 

0.6-.75 

TABLE   XLJI 
OTHER  ANALYSES  OF  THE  EMBRYO  AND  FULLY  GROWN  FETUS* 


AGE 

TOTAL 
WEIGHT 

DRY 

MATTER 

WATER 

DRY  MATTER  CONTAINS 

Ash 

Protein 

Fat 

4  mo  

6  mo 

Grams 
36.5 
361.8 
3294.0 

Grams 
3.00 
39.10 
855.52 

Grams 
33.5 
322.7 

2440.8 

Grams 
0.33 
7.01 
83.00 

Grams 
1.77 
24.13 
388.69 

Grams 
0.20 
2.60 
299.7 

Full  grown 

The  figures  in  Table  XLII  confirm  those  of  the  previous 
table  in  a  general  way  in  showing  that  the  growth  of  the 
fetus  is  mostly  during  the  last  three  or  four  months  of  in 
utero  life. 

1  "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  I,  p.  377. 

2  "Des  Kindes  Ernahrung,"  Czerny-Keller,  p.  87. 


262 


Principles  of  Human  Nutrition 


TABLE    XLIII1 

COMPOSITION  OF  THE  ASH  OF  A  NEW-BORN  CHILD  l 


IN  TOTAL  ASH 

IN  1.000  GRAMS 
BODY  WEIGHT 

Potassium  oxid  (potash)       .     . 
Sodium  oxid  (soda)      .... 
Calcium  oxid  (lime)     .... 
Magnesium  oxid  (magnesia) 
Ferric  oxid     

Grams 

1.64 
6.20 
25.40 
0.67 
1.15 

Grams 

0.88 
3.35 
13.73 
0.36 
0.61 

Phosphorus  pentoxid  .... 
Chlorine    

22.81 
3.50 

12.25 
1.89 

61.37 

33.07 

These  tables  set  forth  other  facts  than  that  the  body  of 
the  fetus  and  new-born  infant  consists  of  ash,  protein,  and 
fat.  It  is  evident  that  at  least  75  per  cent  of  the  dry  sub- 
stance of  the  former  is  added  during  the  last  three  months 
of  intra-uteririe  life,  and  that  the  daily  addition  is  small, 
amounting  on  the  average,  during  the  period  of  rapid 
growth,  to  about  3  grams  of  protein,  3.5  grams  of  fat,  and 
0.6  to  0.7  gram  of  ash  elements. 

248.  Sources  of  fetal  growth.  —  Fetal  growth  may  be\ 
derived  from  either  of  two  sources,  the  food  of  the  mother J 
or  the  material  already  deposited  in  her  body.  If  her  food 
is  sufficient  to  supply  both  her  own  needs  and  those  of  the 
growing  fetus,  then  she  will  sustain  no  body  loss ;  but  with 
food  insufficient  to  meet  the  demands  in  these  two  direc- 
tions, the  body  substance  of  the  mother  will  be  transferred 
to  the  child.  Doubtless  both  conditions  occur,  as  is  indi- 


1  "Des  Kindes  Ernahrung,"  Czerny-Keller,  p.  90. 


Food  Demands  During  Pregnancy  263 

cated  by  the  facts  that  many  mothers  during  pregnancy 
do  not  increase  in  weight,  while  others  become  as  many 
pounds  heavier,  at  least,  as  the  weight  of-  the  fetus  with 
its  surrounding  liquids  and  membranes.  If  the  mother 
does  not  increase  in  weight,  her  own  substance  must  have 
diminished. 

249.'  Food  demands  during  pregnancy.  —  The  impor- 
tant question  is,  what  are  the  special  food  needs,  if  any,  of 
the  gravid  woman  ? 

It  is  clear  that  in  the  kinds  of  nutrients  utilized,  the  food 
needs  of  the  pregnant  woman  do  not  differ  from  the  ordi- 
nary needs  of  the  human  organism.  If  these  needs  are 
special,  it  is  in  the  amount  of  nutrients  required  rather 
than  in  their  kind.  There  is  certainly  a  tendency  to  over- 
estimate the  demands  made  upon  the  parent  organism  for 
the  growth  of  the  unborn  child.  For  the  first  two  hundred 
days,  the  fetal  growth  does  not  call  for  over  1  gram  of 
dry  matter  per  day,  and  probably  not  even  that.  This 
demand  is  hardly  appreciable  when  the  food  eaten  each 
day  ordinarily  carries  over  500  grams  of  dry  matter. 
During  the  last  three  months  of  pregnancy,  in  which 
period  three-fourths  of  the  fetal  growth  occurs,  the  daily 
deposition  of  dry  matter  does  not  reach  ten  grams  per  day, 
which  certainly  does  not  call  for  a  large  increase  in  the 
food  eaten  by  the  mother. 

250.  Energy  use. — But  while  the  early  demands  for  corP 
structive  purposes  during  pregnancy  are  small,  are  there 
not  increased  metabolic  activities  on  the  part  of  the  parent 
organism  that  require  an  increased  use  of  energy,  that  is 
an  increased  oxidation  of  food  compounds?  There  are 
several  reasons  why  we  would  expect  this  to  be  the  case. 


264  Principles  of  Human  Nutrition 

First  of  all,  there  is  the  work  of  blood  circulation  in  the 
body  of  the  unborn  child,  which  is  accomplished  by  the 
muscular  contractions  of  the  fetal  heart,  and  this  requires 
an  expenditure  of  energy  from  some  source.  Besides  this, 
the  weight  of  the  pregnant  woman  is  increased,  except  in 
cases  of  insufficient  nutrition,  and  energy  needs  are  in 
general  in  proportion  to  weight.  The  assimilative  pro- 
cesses are  intensified  also.  In  one  case,  at  least,  the  rate 
of  the  heart  beats  of  the  pregnant  woman  has  been  found 
to  increase  beyond  the  rate  previous  to  conception,  thus 
adding  to  the  internal  work  performed.  In  the  same 
investigation  by  Magnus-Levy,  the  rate  of  respiration 
increased,  adding  still  further  to  muscular  activity.  To 
offset  these  factors  it  often  happens  that  the  mother  is  less 
active,  especially  during  the  last  two  or  three  months  of 
pregnancy,  at  the  time  when  the  increased  demand  of 
food  would  appear  to  be  greatest. 

Accurate  observations  on  the  energy  exchange  (oxida- 
tion) during  pregnancy  are  somewhat  meager  in  number 
where  women  have  been  the  experimental  subjects. 
Magnus-Levy 1  followed  the  use  of  oxygen  through  the 
entire  period  of  pregnancy  of  a  woman,  beginning  with  the 
third  month.  Observations  were  also  made  in  the  non- 
pregnant  period.  A  quite  constant  and  fairly  uniform 
increased  use  of  oxygen  occurred,  being  greatest  in  the 
ninth  month,  when  it  amounted  to  80  cubic  centimeters  per 
minute,  or  25  per  cent  above  the  normal.  Experimental 
data  with  two  other  women  gave  no  such  increase,  and  so 
our  conclusions  must  be  inferential  rather  than  based  upon 
scientific  proof.  It  is  certainly  true,  nevertheless,  that 

1  "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  I,  p.  379. 


Diet  for  Pregnant  Woman  265 

fetal  growth  makes  demands,  though  not  large,  on  the 
nutrition  of  the  mother,  if  her  body  substance  is  to  be 
defended  from  loss ;  and  it  seems  more  than  probable  that 
the  internal  work  of  the  parent  organism  is  somewhat  in- 
creased, requiring  the  expenditure  of  more  energy. 

251.  Diet  for  pregnant  woman.  —  At  the  same  time,  it 
should  not  be  assumed  that  the  diet  of  a  pregnant  woman 
should  be  largely  increased,  or  that  her  needs  require  a  diet 
unusual  in  kind.  (An  ordinary  mixed  diet  that  is  adapted 
to  sustain  a  woman  doing  moderate  work  is  certainly 
sufficient  for  the  gravid  mother.  \The  diet  should  be 
judiciously  selected,  however.  The^extensive  use  of  such 
foods  as  pastry,  cakes,  sweets,  and  all  similar  materials, 
largely  carbohydrates,  with  a  marked  deficiencj^  in  protein 
and  the  ash  elements,  should  be  avoided.  Reference  to 
the  tables  on  p.  261  shows  that  the  body  of  the  new-born 
child  weighing  about  7  pounds  contains  over  300  grams  pro- 
tein and  60  to  80  grams  of  ash,  more  than  three-fourths  of 
the  latter  being  phosphoric  acid  and  lime.  A  simple  diet 
made  up  of  meats,  milk,  and  eggs  in  moderate  proportions, 
and  grain,  vegetable,  and  fruit  preparations  which  carry  as 
nearly  as  possible  the  unmodified  composition  of  the  natural 
products,  will  be  found  sufficient  for  all  the  needs  of 
the  prospective  mother.  Several  authors  publish  dietary 
standards  for  pregnant  women,  which  vary  greatly;  but 
except  in  the  case  of  institutions,  wrhere  a  general  regula- 
tion of  the  food  supply  is  possible,  such  standards  will  be 
applied  to  only  a  small  extent.  If  a  woman  reasonably 
satisfies  a  normal  appetite  from  food  selected  as  indicated 
above,  all  real  requirements  will  be  met.  The  caution  is 
that  an  appetite  abnormal  in  its  desires  should  be  con- 


266  Principles  of  Human  Nutrition 

trolled,  and  that  both  excessive  eating  and  overindulgence 
in  foods  markedly  deficient  in  the  ash  elements  and  protein 
be  kept  in  check.  Abnormal  conditions  require  the  ad- 
vice of  a  physician. 

B.    FEEDING  OF  THE  CHILD  AFTER  BIRTH  WITH 
MOTHER'S  MILK 

252.  Mother's   milk  best.  —  After  birth,   the    natural 
food  of  the  human  young,  and  that  which  is  best  adapted 

;  to  its  physical  welfare  under  normal  conditions,  is  its 
mother's  milk.  Physicians,  nurses,  and  modern  science 
unite  in  declaring  that  this  is  trie  food  which  best  insures 
the  health,  development,  and  good  physical  quality  of  the 
young  child.  Statistics  confirm  this  conclusion.  In 
1890  there  were  born  in  Berlin  alone  49,362  children. 
Before  the  end  of  a  year,  12,623  died,  of  which  1588  had 
been  breast-fed  and  8008  fed  on  cow's  milk.  Further 
statistics  show  of  these  fed  on  mother's  milk  one  in  thirteen 
died,  while  of  those  brought  up  by  hand  one  out  of  every 
two  died.  These  figures  require  no  comment.  Notwith- 
standing such  ominous  facts,  thousands  of  infants  are  fed 
from  a  bottle  on  some  other  food  when  circumstances  do  not 
render  it  necessary.  A  mother  who  selfishly  refuses  to 
feed  her  child  from  the  fountains  of  her  own  life,  merely 
because  of  the  confinement  or  inconvenience  it  occasions, 
fails  to  meet  one  of  her  highest  obligations,  jeopardizes  the 
life  of  her  offspring,  and  hazards  her  right  to  be  called 
"  mother."  The  case  is  different  when  imperative 
demands  of  another  kind  or  abnormal  conditions  of  milk 
secretion  or  of  health  render  artificial  feeding  necessary. 

253.  The  composition  of  human  milk.  —  In  discussing 


Mother's  Milk 


267 


infant  nutrition  from  the  natural  source,  a  logical  considera- 
tion of  the  subject  requires  that  we  first  learn  what  is  the 
composition  of  human  milk.  A  study  of  the  records 
reveals  the  fact  that  the  milk  secreted  by  different  indi- 
viduals varies  greatly,  and  there  is  by  no  means  an  agree- 
ment among  the  average  figures  that  have  been  compiled 
by  different  authorities.  There  follows  the  average  compo- 
sition of  human  milk  as  presented  by  various  compilers :  — 


TABLE    XLIV 
AVERAGE  COMPOSITION  OF  WOMAN'S  MiLK1 


PFEIFFER 

HEUBNER 
HOFFMAN 

ADRIANCE 

GURARD 

JOHANNE- 

8EN 

Dry  matter 
Ash    .... 
Protein    .     .     . 
Sugar      .     .     . 
Fat     .... 

Per  Cent 
11.78 
0.19 

1.94 
6.30 
3.10 

Per  Cent 

12.34 
0.21 
1.03 
7.03 
4.07 

Per  Cent 
12.04 
0.17 
1.17 

6.80 
3.90 

Per  Cent 

Per  Cent 

0.19 

1.18 

7.18 
3.90 

1.10 

4.67 
3.21 

CAMERER  & 
SALDNER 

SCHLOSSMAN 

CARTER  & 
RICHMANS 

LEHMAN 

LUFF 

Dry  matter 
Ash     .     .     .    .. 
Protein   .     .     . 
Sugar      .     .     . 
Fat     .... 

Per  Cent 

11.95 
0.21 
1.03 
6.56 
3.38 

Per  Cent 

Per  Cent 
11.96 

0.26 
1.96 
6.59 
3.07 

Per  Cent 

11.7 
0.2 

1.7 
6.0 

3.8 

Per  Cent 
11.49 

0.34 
2.35 
6.39 
2.41 

1.56 

6.95 
4.83 

The  preceding  figures  fail  to  show  the  great  range  of 
variation.     This  may  be  illustrated  by  a  statement  of  the 

1  Mostly  from  "  Des  Kindes  Ernahrung,"  Czerny-Keller,  pp.  417-418. 


268 


Principles  of  Human  Nutrition 


maximum  and  minimum  percentages  compiled  by  Pfeiffer, 
the  samples  being  only  those  taken  more  than  eleven  days 
after  parturition. 

TABLE    XLV 

PER  CENT 

Dry  substance 8.23-15.56 

Ash       0.10-  0.45 

Protein 1.05-  3.04 

Sugar 4.22-  7.65 

Fat 0.76-  9.05 

Analyses  of  mother's  milk  are  occasionally  made  in  the 
laboratory  of  New  York  Agricultural  Experiment  Station 
at  the  request  of  physicians  and  others.  The  table  which 
follows  shows  the  results  of  eleven  such  analyses. 

TABLE    XLVI 

ANALYSES  OF  HUMAN  MILK  MADE  AT  THE  LABORATORY  OP 
THE  NEW  YORK  AGRICULTURAL  EXPERIMENT  STATION 


TOTAL  SOLIDS 

ASH* 

PROTEIN 

SUGAK  2 

FAT 

(1) 

'(2) 
(3) 
(4) 
(5) 
(6) 
(7) 
(8) 
(9) 
(10) 
(11) 

Per  Cent 

10.89 
10.51 
10.63 
12.58 

Per  Cent 

0.20 
0.20 
0.20 
0.20 

Per  Cent 
1.20 

1.48 
1.45 
1.34 
1.01 
1.20 
1.26 
1.53 
1.64 
1.44 
1.69 

Per  Cent 

7.20 
7.07 
7.98 
7.84 

Per  Cent 
2.29 

1.76 
2.00 
3.20 
1.21 
2.10 
4.00 
3.83 
1.93 
3.05 
2.50 

11.12 
12.18 
12.24 
10.67 
13.15 
13.08 

0.20 
0.20 
0.20 
0.20 
0.20 
0.20 

7.62 
6.72 
6.68 
6.90 
8.46 
7.69 

11.70 

0.20 

1.42 

7.42 

2.66 

1  Assumed. 


2  Determined  by  difference. 


Mother's  Milk 


269 


These  figures  showing  such  wide  departure  from  what 
may  be  regarded  as  normal  milk  are  an  abundant  justifica- 
tion for  the  recommendation  that  in  any  instance  where 
a  nursing  child  is  not  physically  prosperous  the  mother's 
milk  should  be  investigated  both  as  to  quantity  and 
quality. 

254.  Conditions     affecting    mother's     milk.  —  Certain 
causes  which  are  to  be  noticed  and  that  may  operate  to 
modify  the    mother's    milk    such    as    food,   medication, 
exposure,   and  nervous    condition,    are   those   which   are 
under  control.     Other  possible  causes  are  those  that  are 
not  under  control ;  and  which  may  be  termed  "  natural." 

255.  Period  of  lactation.  —  Among  the  latter  it  is  very 
definitely  shown  that  as  the  period  of  lactation  progresses 
the  proportions  of  ash*  and  protein  in  the  milk  diminish, 
especially  during  the  first  few  weeks. 

Several  authorities  give  figures  that  substantiate  this 
statement.1 

TABLE    XLVII 

EFFECT  OF  PERIOD  OF  LACTATION 


PFEI 

FFEB 

ADRI 

ANCB 

Protein 

Ash 

Protein 

Ash 

1st  month   

Per  Cent 
2.97 

Per  Cent 

0.237 

Per  Cent 

1.55 

Per  Cent 
0.21 

2d    month 

204 

0184 

1.54 

0.17 

3d   month   

1  99 

0.184 

1.49 

0.19 

llth  month   

1.47 

0.145 

0.64 

0.18 

12th  month   . 

1  73 

0.160 

1.18 

0.14 

13th  month  

1.65 

0.155 

1.02 

0.16 

1  "  Des  Kindes  Ernahrung,"  Czerny-Keller,  p.  419. 


270      *        Principles  of  Human  Nutrition 

A  gradual  rise  in  the  percentage  of  fat  occurs  in  the  pro- 
gressive portions  of  milk  that  are  drawn ;  that  is,  the  more 
nearly  the  mammary  gland  is  emptied,  the  richer  the  milk 
is  in  fat.  Account  should  be  taken  of  this  fact  in  selecting 
a  sample  for  analysis,  that  is,  a  full  breast  should  be  entirely 
emptied  by  artificial  means  and  a  sample  taken  of  the  whole 
quantity  after  thorough  mixing.  It  may  also  be  said  that, 
as  a  rule,  the  richness  of  human  milk  in  fat  is  inversely  as 
the  total  amount  of  milk  secreted. 

256.  Individuality.  —  There  is  also  the  effect  of  indi- 
viduality, as  shown  by  the  tables  on  p.  268,  which  will  be 
considered  more  fully  later. 

257.  Demands  on  food  for  milk   secretion.  —  As  the 
/secretion  of  milk  is  wholly  dependent  upon  the  mother's 
\  food,  unless  she  is  underfed  and  contributes  from  her 
\body  substance,  her  nutrition  is  a  matter  of  fundamental 

importance.  All  considerations  of  this  phase  of  the  nour- 
ishment of  the  child  must  be  based  upon  the  amount  and 
composition  of  the  milk  which  it  consumes.  Authorities 
who  have  investigated  this  matter  are  somewhat  at  va- 
riance in.  the  figures  which  they  give  for  the  milk  secretion 
of  the  human  mother.  If  it  is  measured  by  what  the 
infant  takes,  and  there  is  no  unused  surplus  artificially 
drawn,  an  average  amount  is  probably  300  grams  (10.6  oz.) 
daily  for  the  first  week  and  at  the  end  of  the  fifth  month 
not  far  from  1000  grams  (35.5  oz.)  daily.1  If  this  milk  is 
of  average  composition,  it  would  contain  in  each  day's  pro- 
duction at  the  two  periods  approximately  the  dry  matter 
and  ingredients  stated  as  follows  :  — 

1See  "Des  Kindes  Ernahrung,"  pp.  351-353. 


Food  and  Milk  Secretion 


271 


TABLE    XLVIII 
SOLIDS  IN  MOTHER'S  MILK 


FIRST  WEEK 

TWENTY-SECOND 

WEEK 

Dry  matter                              .     . 

Grains 
354 

Grams 
1180 

Ash       

0.6 

20 

Proteins                                    .     . 

46 

15  4 

Sugar    .'     , 

19.8 

660 

Fat                                           .     . 

102 

345 

Energy  (calories)     .     .     .     .     . 

189.1 

636.1 

The  increase  of  milk  secretion  seems  to  correspond  to  the 
increased  demands  of  the  child,  and  proceeds  with  a  fair 
degree  of  regularity.  In  those  cases  where  more  than  one 
child  is  suckled,  the  daily  production  sometimes  becomes 
much  greater  than  when  only  one  child  is  at  breast,  rising 
in  observed  instances  to  1750  grams  (62.5  oz.)  or  more 
daily.  Under  ordinary  circumstances  with  one  child  the 
mother  is  likely  to  be  called  upon  to  supply  on  the  average 
about  800  grams  of  milk  daily  from  the  fourth  to  the 
twentieth  week.  This  milk,  if  of  average  composition, 
would  contain  94.6  grams  dry  matter,  1.6  grams  ash, 
12  grams  protein,  54.4  grams  sugar,  and  26.4  grams  fat,  the 
combined  energy  of  these  nutrients  being  518  calories. 
(These  facts  are  convincing  evidence  that  the  demands  on 
the  mother  during  the  nursing  period  are  much  greater 
than  during  the  period  of  pregnancy,  indeed,  they  are 
•demands  that  should  receive  adequate  recognition  in  the 
mother's  diet,  especially  after  the  first  few  weeks. 


272  Principles  of  Human  Nutrition 

258.  Necessary  dietary.  —  The  American  dietary  stand- 
ard for  women  doing  light  muscular  work  is  2400  calories, 
and  with  women  doing  moderate  work  it  is  2700  calories. 
If  the  food  equivalents  of  these  energy  expenditures  are 
necessary  to  maintain  ordinary  household  activity  without 
gain  or  loss  of  body  substance,  the  additional  demands  of 
the  nursing  child  require  that  the  food  consumed  shall  be 
increased  one-fifth,  or  even  more,  as  the  child  increases  in 
size.     It    is    often    noticed    that    nursing   mothers    grow 
"  thin,"  which  is  undoubtedly  due  to  insufficient  nutri- 
tion, especially  when  the  milk  secretion  reaches  1000  grams 
or  above  that  quantity,  the  dry  matter  of  which  represents 
not  less  than  one-fourth  the  daily  ration  of  a  housewife 
doing  light  work. 

259.  Effect  of  insufficient  diet.  —  The  physical  welfare, 
not  only  of  the  nursing  mother,  but  also  of  her  child,  is 
dependent   upon   her   proper  nourishment.     Observations 
indicates  that  when  the  mother's  diet  is  insufficient,  the  \ 
milk  is  less  in  quantity  and  possibly  poorer  in  quality  J 
The  failure  of  an  infant  at  breast  to  grow  as  it  should 
may  sometimes  be  due  to  lack  of  sufficient  food,  and  this 
possibility  should  receive  careful  attention.     It  should  not 
be  assumed,  however,  that  in  all  cases  the  necessary  milk 
secretion  can  be  secured  through  abundant  diet.     Certain 
mothers  seem  to  have  constitutional  limitations  of  capacity 
to  secrete  milk  that  cannot  be  overcome  by  a  generous 
diet,  or  by  the  kind  of  diet. 

260.  Effect  of    foods  on  milk  secretion.  —  There  are 
many  "  old  wives'  sayings  "  concerning  the  relation  of  food 
to  the  mother's  milk  that  have  no  foundation  in  fact.     It  is 
believed  by  some  that  copious  drinking,  or  the  free  use  of 


Food  and  Milk  Secretion  273 

watery  foods  like  soups  or  porridges,  promotes  the  milk 
flow.  Nothing  could  be  more  erroneous.  The  free  use 
of  milk  is  recommended,  on  the  ground  that  "  milk  makes 
milk."  While  it  is  true  that  a  reasonable  amount  of  milk 
forms  a  very  useful  part  of  the  diet  of  a  nursing  mother, 
and  supplies  all  the  needed  materials  for  the  secretion  of 
human  milk,  it  is  also  true  that  other  foods,  such  as  meat, 
eggs,  grain  foods,  and  vegetables,  sustain  milk  secretion  in  a 
very  satisfactory  way  when  they  are  wisely  combined. 
The  constituents  of  milk  are  a  secretion  of  the  mammary 
glands  in  which  the  casein  and  milk  fats  are  elaborated 
out  of  the  raw  materials  supplied  by  the  food  or  the  mother's 
tissues.  These  bodies  are  not  filtered  out  of  the  blood  as 
such  from  the  digested  food  compounds.  If  this  were  so, 
then  the  food  would  have  a  very  direct  and  extensive  influ- 
ence on  the  quality  of  the  milk,  which  is  not  the  case. 
With  species  and  breeds  of  animals  the  amount  and  kind  of 
milk  are  determined  by  the  specific  activity  of  the  secret- 
ing glands,  and  no  variations  of  food  will  cause  a  Holstein 
cow  to  give  Jersey  milk  or  will  cause  any  individual 
animal  to  abandon  her  constitutional  habit  of  milk  secre- 
tion, and  the  same  is  true  of  individuals  of  the  human 
species. 

261.  Procedure  when  milk  is  abnormal.  —  It  some- 
times happens  that  a  mother's  milk  is  abnormal  in  its 
quality,  that  is,  it  may  be  unusually  poor  or  unusually 
rich,  or  may  have  one  constituent  in  unusual  proportions. 
When  this  is  true,  and  the  child  is  unfavorably  affected, 
the  remedy  lies  in  resorting  to  artificial  feeding,  and  not 
in  trying  to  modify  the  milk  through  the  food  supply. 
The  attempt  to  change  the  richness  of  human  milk  or  the 


274  Principles  of  Human  Nutrition 

jrelative  proportions  of  its  constituents  by  giving  the 
mother  watery  food,  or  food  especially  rich  in  one  con- 
stituent such  as  protein  or  fat,  is  bound  to  fail  in  its  pur- 
pose. All  that  is  required  is  that  the  food  shall  be  suffi- 
cient in  quantity  and  not  markedly  insufficient  in  any 
needed  constituent.  A  diet  made  up  of  meats  and  fish  in 
reasonable  proportions,  eggs,  milk,  bread,  breakfast  foods 
in  which  the  constituents  of  the  whole  grain  are  practically 
all  retained,  fruits  in  moderate  quantity,  and  vegetables  of 
such  kinds  and  in  such  quantities  as  do  not  cause  digestive 
disturbances,  furnishes  an  adequate  basis  for  abundant 
milk  secretion. 

262.  Effect  of  mother's  food  upon  child.  —  The  asser- 
tion is  often  heard  that  a  child  has  been  harmfully  affected 
by  some  food  substance  that  entered  into  the  mother's 
diet,  or  by  some  medicine  she  took.  There  are  two  ways 
in  which  it  is  conceivable  that  the  food  of  the  mother  rm 
work  injury  to  the  child:  (1)  the  diet  affecting  th< 
mother's  health,  with  an  accompanying  reaction  on  th< 
milk  secretion,  and  (2)  by  the  direct  transfer  to  the  mill 
of  substances  in  the  mother's  food.  Overeating,  sudden 
changes  in  the  diet,  and  the  use  of  foods  that,  with  a  par- 
ticular person  are  known  to  cause  a  disturbance  of  the 
digestion,  may  react  on  the  milk  secretion,  and  these 
causes  should  be  avoided.  Concerning  the  influence  of 
particular  foods  on  the  child  through  the  direct  transfer- 
ence to  the  mother's  milk  of  certain  compounds,  there  is 
much  tradition  and  little  exact  knowledge.  Doubtless 
some  foods  are  regarded  as  undesirable  for  the  nursing 
mother  without  good  reason,  their  bad  reputation  arising 
either  from  the  results  of  eating  an  excessive  quantity, 


Food  and  Milk  Secretion  275 

or  because  the  illness  of  some  child  has  been  coincident  with 
the  use  of  a  certain  food  when  it  was  not  the  disturbing 
factor.  Tradition  teaches  that  acid  materials  such  as 
fruits  and  pickles,  and  condiments  such  as  the  spices  and 
peppers,  dangerously  affect  the  mother's  milk.  Doubtless 
popular  notions  greatly  exaggerate  the  real  facts.  There 
are  no  well  established  facts  which  justify  the  conclusion 
that  a  nursing  mother  may  not  eat  acid  fruits  in  moderation 
if  under  ordinary  conditions  she  is  accustomed  to  do  so  with 
comfort.  It  has  been  stated  to  the  writer  that  beans, 
boiled  cabbage,  and  other  vegetables  likely  to  cause  in- 
testinal fermentations  should  be  excluded  from  the  diet  of 
a  nursing  mother ;  but  this  assertion  seems  to  rest  on  hear- 
say, and  not  on  demonstrative  experience.  It  is  hard  to 
understand  how  these  common  foods,  when  eaten  in 
reasonable  quantities  and  with  regularity  as  to  kind  and 
quantity,  can  cause  the  mother's  milk  to  be  harmful.  A 
significant  fact  is  that  cow's  milk  produced  from  a  ration 
of  which  acid  silage  forms  a  generous  part  may  be  safely 
fed  to  infants,  as  the  writer  knows  from  observation. 
Milk  from  a  general  milk  supply,  or  even  that  known  as 
"  sanitary "  or  "  certified,"  is  produced  from  a  great 
variety  of  foods,  including  silage,  roots,  and  by-product 
feeding  stuffs,  and  yet  when  such  milk  is  sound,  it  seems 
to  be  a  safe  food  for  infants  in  hundreds  of  cases. 

263.  Effect  of  food  upon  cow's  milk.  —  It  is  hardly  to 
be  expected  that  the  human  and  the  bovine  mother  are 
subject  to  greatly  unlike  laws  in  the  relation  of  food  to 
milk  secretion,  and  consequently  the  outcome  of  experi- 
ments with  cows  to  determine  the  effect  of  feeding  various 
substances  on  the  composition  of  milk  is  of  importance 


276  Principles  of  Human  Nutrition 

in  this  connection.  It  has  been  found,  as  stated,  that 
sudden  and  pronounced  changes  in  the  food  of  the  cow 
may  have  a  temporary  effect  on  the  proportions  of  milk 
constituents,  an  effect  only  temporary,  however.  The 
bovine  mammary  glands  have  a  constitutional  gauge  not 
easily  changed,  if  changed  at  all.  It  also  appears  that 
heavy  feeding  with  certain  vegetable  oils,  like  cottonseed, 
linseed,  and  sesame  oils,  may  appreciably  modify  the  rela- 
tive proportion  of  individual  fats  in  the  milk  fat,  and  that 
the  physical  condition  of  the  butter  fat  is  modified  to  a 
small  degree  because  of  a  change  in  the  relative  proportion 
of  the  harder  to  the  softer  fats  in  the  food.  Various  in- 
vestigators, after  feeding  a  vegetable  oil  heavily,  have 
discovered  its  characteristic  .fats  in  the  milk  of  the  ex- 
perimental animal,  but  only  in  very  small  proportions. 

But  granting  all  these  facts,  and  also  that  the  milk  of 
the  human  mother  would  be  similarly  affected  by  the  food 
constituents,  especially  the  fats,  there  is  nothing  in  this  to 
indicate  that  the  milk  thus  becomes  harmful,  because  the 
changes  brought  about  are  simply  a  slightly  different  pro- 
portion of  food  compounds  of  known  value.  We  are 
justified  in  concluding,  then,  that  the  foods  which  the  nurs- 
ing mother  may  eat  include  practically  the  whole  list,  pi 
vided  the  diet  is  kept  up  on  a  fairly  uniform  basis  as 
kind  and  quality  of  material,  involving  no  sudden  change 
and  that  from  it  is  excluded  those  foods  which  in  particulaj 
cases  cause  discomfort. 

264.  Effect  of  medicines  taken  by  mother.  —  When  we 
come  to  consider  the  effect  on  her  milk  of  administering 
medicinal  substances  to  the  mother,  the  evidence  at  hand 
is  more  definite.  It  has  been  conclusively  shown  that 


Effect  of  Psychic  Condition  277 

iodin  and  salicylic  acid,  or  their  compounds,  antipyrin, 
mercury,  and  other  substances  may  pass  into  the  milk, 
though  in  very  minute  quantities,  but  probably  in  sufficient 
amounts  to  affect  the  child.  For  this  reason  a  nursing 
mother  should  take  medicine  only  under  the  advice  and 
direction  of  a  physician. 

265.'  Effect  of  psychic  condition.  —  The  psychic  or 
"  nervous  "  condition  of  the  mother  may  have  a  profound 
influence  upon  the  physical  welfare  of  the  nursing  infant. 
There  is  abundant  evidence  that  continued  grief,  melanA 
cholia,  or  great  anxiety  may  seriously  affect  the  child, 
causing  a  loss  of  weight  and  sometimes  bowel  disturbances.  I 
From  such  causes,  as  well  as  by  severe  chill  or  some  other 
unusual  physical  experience,  the  secretion  of  milk  may 
suddenly  cease.  There  is  evidence,  too,  that  from  these 
causes  the  milk  may  be  so  modified  as  to  become  harmful, 
though  just  what  occurs  is  not  known.  It  is  'a  strange  and 
unexplained  fact.  To  suggest  that  some  toxic  body  is 
developed  through  nerve  reaction  is  simply  to  advance  an 
hypothesis.  It  is  important,  therefore,  that  the  mother 
avoid  as  far  as  possible  all  forms  of  disagreeable  mental 
experience  and  maintain  mentally  and  physically  a  con- 
dition of  repose  and  comfort.  If  severe  experiences  are 
unavoidable,  it  may  be  wise  or  even  necessary  to  transfer 
the  child  to  artificial  feeding  or  to  a  wet  nurse. 

266.  Precautions  in  feeding.  —  There  are  certain  pre- 
cautions which  should  be  observed  in  feeding  infants, 
whether  they  receive  mother's  milk  or  are  given  artificial 
food.  (*The  feeding  should  be  regular  and,  with  a  very 
young  infant,  once  in  two  hours  is  probably  good  prac- 
tice, although  a  single  rule  cannot  be  rigidly  followed  in 


278  Principles  of  Human  Nutrition 

all  cases.  It  is  a  serious  mistake  for  a  mother  to  nurse 
her  child  too  frequently  as  a  means  of  quieting  it  when- 
ever it  is  fretful.  Such  a  practice  may  result  in  over- 
loading the  child's  stomach.  As  the  child  grows  older 
the  frequency  of  feeding  may  be  diminished. 

The  infant  should  be  weighed  frequently  to  determine 
its  rate  of  gain.  It  should  be.  said,  however,  that 
plumpness  or  the  laying  on  of  fat  is  not  necessarily  an 
indication  of  physical  prosperity;  indeed,  a  child  may 
become  too  fat  for  its  physical  good.  The  real  essen- 
tial is  the  growth  of  the  basal  tissues,  and  the  character 
of  the  food  has  much  to  do  with  this.  Artificially  fed 
children  are  often  more  fleshy  than  those  fed  at  the 
breast,  whereas  the  latter  may  in  reality  be  making  the 
more  desirable  growth. 

C.    ARTIFICIAL  FEEDING  OF  INFANTS 

There  is  no  question  but  that  in  general  the  develop- 
ment and  physical  well  being  of  the  young  child  is  most 
fully  insured  when  its  food  is  mother's  milk.  Sometimes, 
however,  the  necessities  of  the  case  require  a  resort  to 
some  other  food.  Under  such  circumstances  use  may  be 
made  of  the  milk  of  some  other  mammal,  such  as  the  cow 
or  the  goat,  or  one  of  the  so-called  infant  foods  prepared 
wholly  or  in  part  from  one  or  more  of  the  cereal  grains 
may  be  fed,  but  as  will  be  seen,  these  artificial  prepara- 
tions should  be  avoided  with  children  in  the  nursing 
period,  whenever  possible. 


Artificial  Feeding  of  Infants 


279 


TABLE    XLIX 
COMPARISON  OF  Cow's  AND  MOTHER'S  MILK 


AVERAGE 
Cow's  MILK 

AVERAGE 
MOTHER'S  MILK 

Total  solids    

Per  Cent 

1290 

Per  Cent 
11  80 

Ash      V    

070 

020 

Proteins 

320 

1  54 

Sugar    

5  10 

661 

Fat  . 

3.90 

3.45 

Because  the  ash  constituents  are  important  as  con- 
structive material,  there  is  also  good  reason  for  comparing 
the  two  kinds  of  milk  on  this  basts. 


Cow's  Milk 

Human  Milk 

Potassium  oxid                  .     .     . 

Per  Cent 

1.67 
1.05 
1.54 
0.20 
0.003 
1.86 
1.60 

Per  Cent 
0.58 

0.17 
0.24 
0.05 
0.004 
0.35 
0.32 

Sodium  oxid        .     .     .     .     .     . 

Calcium  oxid 

Magnesium  oxid      ..... 

Iron  oxid  

Phosphorus  oxid      .     .     . 
Chlorine    

100  PARTS  MILK  CONTAINS  IN  GRAINS 

Cow's  Milk 

Human  Milk 

Potassium  oxid        ..... 

Per  Cent 

0.1776 
0.6972 
0.1671 
0.0231 
0.0021 
0.1911 
0.1368 

Per  Cent 

0.0795 
0.0253 
0.0489 
0.0065 
0.0008 
0.0585 
0.0486 

Sodium  oxid                            »     . 

Calcium  oxid                           •     » 

Magnesium  oxid      

Iron  oxid 

Phosphorus  oxid           .... 

Chlorine                                         . 

IN  100  PARTS  MILK  DRY  SUBSTANCE 


280  Principles  of  Human  Nutrition 

267.  Unlike  composition  of  human  and  cow's  milk.  — 

Experience  has  demonstrated  that  if  cow's  milk  is  to  be 
fed  successfully  to  infants  it  should  be  modified  or  "  hu- 
manized." In  order  to  understand  why  and  how  this  is 
done,  it  is  necessary  to  consider  the  chemical  and  physical 
differences  between  mother's  milk  and  cow's  milk.  The 
chemical  differences  are  well  illustrated  when  we  place  side 
by  side  the  average  composition  of  the  two  kinds  of  milk. 
The  preceding  figures  show  that  while  cow's  milk  and 
mother's  milk  are  in  general  alike  in  the  kind  of  compounds 
they  contain,  they  show  marked  differences  in  their  per- 
centage composition.  The  cow's  milk  is  richer  in  solids,1 
that  is,  has  less  water;  and  these  solids  are  made  up  in 
much  larger  proportion  of  ash  and  protein  than  is  the  case 
with  mother's  milk,  while  in  the  solids  of  the  latter  the 
proportion  of  sugar  is  greater.  The  ash  compounds, 
while  alike  in  kind,  are  not  far  from  three  times  as  abundant 
in  the  cow's  milk  as  in  the  mother's.  These  comparisons 
are  based  on  the  average  composition  of  the  two  kinds  of 
milk.  The  differences  named  are  still  greater  when  the 
cow's  milk  is  from  one  of  the  butter-making  breeds  such 
as  the  Jersey  or  Guernsey,  for  in  this  case  the  percentage 
of  solids  may  be  over  15  per  cent  or  even  16  per  cent,  and 
the  protein  between  4  and  5  per  cent,  especially  if  the  cows 
are  fairly  well  advanced  in  the  period  of  lactation. 

268.  Are  the  compounds  similar  ?  —  We  have  seen  that 
the  classes  of  compounds  and  the  ash  constituents  are  alike 
in  mother's  and  cow's  milk,  but  the  question  naturally 
arises   whether   the   compounds   themselves   are   similar. 
Are  the  protein  bodies  and  the  fats  alike  in  the  two  milks  ? 
A  negative  answer  must  be  given  to  this  question.     There 


M 


Human  Milk  and  Cow's  Milk  Compared     281 

are  several  differences.  As  we  know,  the  protein  of  milk 
is  a  mixture  of  several  nitrogen  compounds,  casein,  al- 
bumin, globulin,  and  others.  These  bodies  do  not  exist 
in  the  same  proportions  in  the  two  milks  under  discussion, 
the  proportion  of  casein  in  the  protein  of  cow's  milk  being 
80  per  cent,  which  is  nearly  twice  as  large  as  in  human 
milk,  'the  soluble  bodies  like  albumin  and  globulin  being 
proportionately  larger  in  the  latter  milk.1  The  signifi- 
cance of  this  fact  lies  in  the  unlike  behavior  of  casein 
and  albumin  toward  acids  and  coagulating  ferments. 
Casein  is  coagulated  at  ordinary  temperatures  by  the 
combined  action  of  acid  and  pepsin,  while  albumin  is  not, 
and  partly  for  this  reason  the  milks  under  comparison 
must  behave  quite  differently  in  the  human  stomach 
when  they  come  in  contact  with  the  gastric  juice.  It 
appears,  too,  that  the  casein  of  cow's  milk  is  riot  quite 
the  same  compound  as  in  mother's  milk.  This  is  shown 
by  a  difference  in  the  proportions  of  the  several  elements 
in  the  casein  from  the  two  sources,  especially  of  the  phos- 
phorus and  sulfur.2 

As  with  protein,  the  fat  of  milk  is  not  a  single  body, 
but  is  a  mixture  of  several  individual  fats,  and  these 
exist  in  the  fat  of  the  two  milks  in  quite  different  pro* 
portions.  As  previously  explained,  the  fats  consist  of 
fatty  acids  united  with  glycerine.  When  freed  from  the 
glycerine,  some  are  solid,  and  some  are  liquids,  at  ordinary 
temperatures;  some  are  volatile  and  gradually  pass  into 
the  air,  especially  when  heated ;  and  some  are  non-volatile, 
or  fixed.  Cow's  milk  contains  more  than  ten  times  as  large 

1  "  Handbuch  der  Milchkunde,"  Sommerfield,  pp.  782-784. 

2  Loc.  cit.,  p.  787. 


282  Principles  of  Human  Nutrition 

a  proportion  of  the  volatile  acids  as  does  human  milk, 
while  the  percentage  of  oleic  acid,  an  oil  at  room  tempera- 
ture, is  much  greater  in  the  latter.     The  combined  effec 
of  these  differences  is  that  mother's  milk  fat  melts  at  th 
lower  temperature,  a  fact  that  is  doubtless  of  some  im/ 
portance  as  related  to  the  ease  of  digestion.1 

269.  Comparison  of  physical  condition.  —  Certain  other 
differences  should  be  noted  that  show  a  marked  difference 
in  the  physical  character  of  the  two  milks.     It  is  well 
understood  that  the  casein  of  milk  is  not  in  solution  therein, 
but  is  held  in  suspension  as  colloidal  particles.     When 
cow's  milk  is  examined  with  the  ultra  microscope,  it  is 
possible  to  see  these  particles,  which  either  by  their  consti- 
tution or  their  abundance  completely  hide  the  fat  globules. 
When  a  similar  examination  is  made  of  mother's  milk, 
no  casein  particles  are  visible,  and  the  fat  globules  show 
in  a  dark  and  apparently  otherwise  empty  space.     This  dif- 
ference can  scarcely  be  due  to  the  less  amount  of  casein  in  the 
mother's  milk,  but  shows  rather  that  the  constitution  of 
the  particles  is  unlike  in  the  two  cases.     The  fat  globules 
of  the  mother's  milk  are  much  smaller  than  in  the  other, 

270.  The    unlike    curdling    of    the    two   milks.  —  The 
practical    bearing  of    all   these  facts  on  the   feeding  of 
children  is  apparent  when  we  come  to  observe  the  unlike 
curdling  of  the  two  milks.     When  a  baby  rejects  cow's 
milk  from  its  stomach,  it  is  easily  seen  that  the  curds  thaij 
have  formed  are  of  some  size  and  show  more  or  less  solidity,! 
that  is,  they  look  decidedly  cheesy.     On  the  contrary ,| 
when  the  food  is  the  mother's  milk,  the  curds  are  not  nearly 
as  evident,  and  are  much  more  light  and  flaky.     The  same 
difference  is  observed  in  the  laboratory  when  acid  is  added 

^oc.  cit.,  p.  796. 


Humanizing  Cow's  Milk  283 

to  the  two  milks.  That  from  the  cow  permits  the  prompt 
and  complete  separation  of  the  casein  by  coagulation,  which 
is  not  the  case  with  woman's  milk,  the  coagulation  being 
quite  different.  The  greater  adaptability  of  mother's 
milk  to  infant  feeding  seems  to  be  due  to  the  difference 
in  the  proportion  of  the  various  compounds  and  to  their 
unlike  physical  condition  rather  than  to  any  inferiority 
of  the  casein,  sugar,  and  fats  of  cow's  milk  in  performing 
the  functions  of  growth  and  maintenance  when  once 
digested.  It  appears  to  be  a  matter  of  ease  of  digestion, 
rather  than  nutritive  function.  One  writer 1  advances  the 
view  that  the  difference,  as  infant's  food,  between  cow's 
milk  and  mother's  milk  is  mostly  due  to  the  larger  pro- 
portion and  consequent  irritating  influence  of  mineral 
salts  in  the  former  rather  than  to  the  differences  in  kind 
and  quantity  of  the  proteins  and  fat,  but  the  facts  cited 
can  hardly  be  ignored  in  favor  of  this  theory.  It  is  not 
strange  that  the  milk  of  the  human  mother  is  better  suited 
to  her  young  than  that  of  any  other  species,  otherwise 
'Nature  would  seem  to  be  a  bungler. 

271.  The  humanizing  of  cow's  milk.  —  There  are  many 
cases  where  it  is  out  of  the  question  for  the  mother  to  feed 
her  child  with  her  own  milk.  Unless  a  "  wet  nurse  "  can 
be  substituted,  resort  must  be  had  to  some  artificial  food, 
the  one  most  commonly  used  being  cow's  milk.  We  have 
seen  that  cow's  milk  differs  from  human  milk  in  the  fol- 
lowing particulars :  — 

L^A  larger  proportion  of  xsolids,  especially  when  it  is 
from  either  Jersey  or  Guernsey"  animals. 

2j^Fwice  as  large  an  average  proportion  of  protein, 
four^fifths  of  which  is  casein,  whereas  in  human  milk  only 

1  The  Lancet,  Jan.  8,  1910. 


284  Principles  of  Human  Nutrition 

two-fifths  of  the  protein  is  casein,  the  soluble  proteins  like 
albumin  being  proportionately  more  in  the  human  milk 
protein. 

much  smaller  proportion  of  milk  sugar  in  the  solids. 
r  A  different  combination  of  fats,  the  mixture  melting 
at  a  lower  temperature  in  mother's  milk. 

When  cow's  milk  is  to  be  fed  to  the  infant,  it  would  seem 
wise  to  eliminate  these  differences  as  fully  as  possible, 
although  a  complete  similarity  to  mother's  milk  can  hardly 
be  reached.  If  cow's  milk  is  diluted  with  an  equal  volume 
of  water,  the  proportion  of  casein  in  the  mixture  becomes 
approximately  like  that  in  human  milk.  But  this  gives 
a  proportion  of  solids  altogether  too  low  for  satisfactory 
results,  and  besides,  the  solids  are  too  poor  in  sugar  and 
fat.  The  sugar  and  fat  not  only  aid  in  nourishing  the  child, 
but  a  greater  proportion  so  divides  the  particles  of  casein 
that  its  coagulation  approaches  more  nearly  that  of  mother's 
milk.  The  desired  result  may  be  practically  accomplished 
by  a  combination  of  cow's  milk,  cream,  milk  sugar  and  barley 
water,  the  latter  adding  more  or  less  albumin  and  other 
soluble  matter  that  still  further  modifies  the  coagulation.,, 

272.  Illustrative  formulae. — The  two  following  for- 
mulae may  serve  to  illustrate  this  method  of  modifying 
cow's  milk. 

As  the  barley  water  carries  some  solid  matter,  it  may  be 
well  to  make  up  the  foregoing  mixtures  to  twenty  ounces 
for  the  first  two  or  three  weeks.  Following  this  more  dilute 
preparation,  a  change  may  be  made  to  the  16-ounce  volume. 
The  proportion  of  solids  in  the  modified  milk  may  safely 
be  allowed  to  increase  progressively  as  the  child  grows 
older.  This  may  be  accomplished  by  using  the  same 


Humanizing  Cow's  Milk 


285 


TABLE    L 

FORMULAE  FOR  MODIFYING  Cow's  MILK 
No.  1 


FORMULA  FOB  AVERAGE  MILK 

Solids 

Ash 

Protein 

Sugar 

Fat 

7  oz.  average  milk  .... 
1  oz.  18  percent  cream  (average) 
i  oz  milk  sugar 

Oz. 

.903 
.26 
.50 

Oz. 

.049 
.005 

Oz. 

.224 
.025 

Oz. 

.357 
.045 
.50 

Oz. 

.273 
.185 

Dilute  with  barley  water  to  16 
oz. 

16  oz.  average  mother's  milk  . 
Composition  modified  milk  . 

1.663 

1.888 

% 
10.4 

.054 
.032 

% 
.34 

.249 
.246 
% 
1.55 

.912 
1.057 
% 
5.70 

.458 
.552 

% 
2.86 

No.  2 


FORMULA  FOR  AVERAGE  JERSEY  OR 
GUERNSEY  MILK 

Solids 

Ash 

Protein 

Sugar 

Fat 

7  oz   milk         

Oz.» 

1.05 
.13 
^0 

Oz. 

.56 
.002 

Oz. 

.273 
.012 

Oz. 

.350 
.022 
.50 

Oz. 

.371 
.090 

\  oz.  18  per  cent  cream      .     . 

Dilute  with   barley  water  to 
16  oz. 

Composition  modified  milk    . 

.461 

% 
2.87 

1.68 

% 
10.5 

.058 

% 
.40 

.285 

% 
1.80 

.872 

% 
5.45 

286  Principles  of  Human  Nutrition 

amounts  of  milk,  cream,  and  milk  sugar,  and  making  up 
the  mixture  to  a  less  volume.  At  the  end  of  ten  or  twelve 
weeks,  the  volume  could  safely  be  reduced  to  14  ounces, 
and  at  five  or  six  months  to  12  ounces. 

It  is  very  commonly  recommended  that  a  certain  pro- 
portion of  lime  water  be  used  in  diluting  cow's  milk.  If 
the  object  of  this  is  to  cause  a  more  desirable  coagulation 
of  the  casein,  it  seems  to  be  more  rational  to  reach  this 
result  by  the  use  of  barley  water  or  by  adding  a  thoroughly 
soluble  cereal  preparation.  It  is  questionable  whether 
it  is  wise  to  neutralize  the  essential  acidity  of  the  gastric 
juice  by  adding  to  the  food  a  free  base  like  calcium  hydrate. 

273.  Accuracy  desirable.  —  Accuracy  in  modifying  milk 
requires  that  the  composition  of  the  milk  and  cream  be 
known.  On  a  commercial  scale  or  in  a  pediatric  hospital 
where  large  numbers  of  children  are  fed,  this  is  possible, 
but  in  the  home  it  is  not,  although  where  a  Babcock 
tester  is  available  a  determination  of  the  fat  and  solids 
may  be  quickly  made.  If  the  milk  is  from  Holstein  or 
other  thin  milk  cows,  it  will  in  general  be  safe  to  use 
8  ounces  with  1 J  ounces  of  cream  and  i  ounce  milk  sugar, 
the  whole  to  be  made  up  to  16  ounces.  With  Jersey  or 
Guernsey  milk  the  formula  given  above  for  that  class  of 
milk  may  be  used.  When  the  family  is  provided  with  high- 
priced  certified  milk,  the  composition  is  generally  known  and 
the  formula  may  be  varied  accordingly.  It  is  sometimes 
recommended  to  take  a  certain  quantity  of  "  top  milk  " 
and  dilute  it  to  a  given  volume ;  but  this  method  is  not  to 
be  commended,  because  top  milk  is  a  very  uncertain  com- 
position. It  will  vary  to  a  marked  degree  with  the  tem- 
perature at  which  the  milk  is  kept ;  while  the  cream  is 
rising,  the  higher  the  temperature  the  richer  the  cream. 


Goat's  Milk  287 

It  will  also  vary  with  the  original  quality  of  the  milk, 
cream  from  thin  milk  containing  less  fat  than  cream  from 
rich  milk,  other  conditions  being  the  same.  If  top  milk 
is  to  be  used,  it  should  be  from  milk  of  a  fairly  uniform 
quality  and  kept  at  practically  the  same  temperature 
from  day  to  day.  , 

274'.  Precautions.  — (A  general  supply  of  mixed  milk 
should  not  be  used  if  it  can  be  avoided?]  Unless  milk 
known  to  be  sanitary  and  of  fairly  uniform  composition 
can  be  procured,  the  milk  of  a  single  cow,  known  to  be 
healthy,  should  be  used*  This  cow  should  not  be  too  far 
advanced  in  the  period  of  lactation,  should  be  rationally 
fed,  and  neither  the  cow  nor  her  milk  and  utensils  should 
come  in  contact  with  a  person  having  an  infectious  disease 
or  recovering  from  such.  The  milk  should  be  drawn 
under  cleanly  conditions,  cooled  at  once,  and  kept  cold  in 
a  sanitary  refrigerator  until  used.  Such  precautions  are 
often  difficult  and  sometimes  impossible  in  large  cities, 
except  for  the  wealthy,  a  fact  which  greatly  enhances  the 
dangers  from  feeding  children  on  cow's  milk,  especially 
during  the  summer  months. 

The  use  of  all  the  knowledge  and  skill  we  now  possess 
does  not  yet  make  it  possible  to  perfectly  simulate  mother's 
milk  by  the  use  of  other  materials.  We  cannot  yet  attain 
nature's  art  in  providing  food  for  the  human  young. 

275.  Goat's  milk  as  infant  food.  —  Within  a  few  years 
much  attention  has  been  given  to  goat's  milk  as  a  food  for 
infants.  The  points  urged  in  its  favor  are  that  one  or 
more  goats  may  be  kept  by  a  family  having  only  a  small 
area  of  land,  thus  insuring  fresh  milk,  that  the  milk  is 
economically  produced,  that  this  species  is  practically  free 


288  Principles  of  Human  Nutrition 

from  tuberculosis,  though  not  entirely  immune,  and,  what 
is  most  important,  satisfactory  results  seem  to  attend  the 
use  of  the  milk.  It  is  objected  that  because  of  the  long 
hair  of  the  goat  the  milk  is  more  likely  to  be  contaminated, 
and  the  offensive  odor  from  the  animal's  skin  is  liable  to 
cause  an  undesirable  flavor  in  the  milk.  Both  these  ob- 
jections may  be  obviated  by  thoroughly  cleaning  the  hair 
and  skin  of  the  animal  and  by  drawing  the  milk  in 
some  yard  or  room  outside  the  living  quarters  of  the 
animals. 

The  composition  of  goat's  milk  appears  to  vary  widely, 
as  is  shown  by  the  following  figures.  Average  analyses 
presented  by  several  authors  show  a  variation  of  the  per 
cent  of  solid  matter  from  7  to  18.  Analyses  of  the  milk 
of  several  goats  have  recently  been  made  at  the  New 
York  Agricultural  Experiment  Station  with  results  as 
shown  in  Table  LI 

It  appears  that  the  quality  of  the  milk  bears  quite  a 
marked  relation  to  the  amount  of  the  yield,  the  smaller 
the  yield  the  larger  the  per  cent  of  solids.  TJiis  is  true  of 
other  mammals. 

Goat's  milk  is  seen  to  be  greatly  unlike  human  milk  in 
its  composition.  It  contains  in  many  instances  not  far 
from  the  same  percentage  of  solid  matter,  but  the  propor- 
tion of  protein  in  the  solids  is  much  higher  and  of  sugar 
much  lower.  The  percentage  of  fat  varies  greatly. 

As  compared  with  cow's  milk,  certain  differences  exist. 
The  fat  globules  of  the  goat's  milk  are  smaller,  and  when  it 
is  coagulated,  the  particles  of  curd  are  finer.  It  is  also 
more  viscous  (sticky).  These  physical  conditions  are 
such  that  cream  does  not  rise  on  raw  goat's  milk  even  on 


Infant  Foods 


289 


long  standing,  but  after  boiling,  a  separation  of  the  cream 
occurs.  The  reasons  are  not  quite  clear  why  goat's  milk 
is  to  be  preferred  to  properly  modified  cow's  milk  for  feed- 
ing children.  The  proteins  have  about  the  same  relative 
proportions  of  casein  and  albumin,  and  there  is  much 
similarity  in  other  respects.  (^The  most  probable  reason  for 
superiority,  if  such  exists,  is  in  the  different  manner  of 
coagulation^)  It  would  seem  that  goat's  milk  of  a  high 
percentage  of  solids  would  be  improved  by  modification  in 
the  manner  recommended  for  cow's  milk. 

TABLE    LI 

ANALYSES  OF  THE  MILK  OF  ELEVEN  INDIVIDUAL  GOATS, 
AUGUST  9,  1910 


WEIGHT, 
MILK 

TOTAL 
SOLIDS 

ASH  ' 

TOTAL 
PROTEIN 

CASEIN 

ALBUMIN, 

ETC. 

FAT 

Pounds 

Per  Cent 

Per  Cent 

Per  Cent 

Per  Cent 

Per  Cent 

Per  Cent 

2.8 

11.47 

0.49 

2.88 

2.12 

0.76 

3.7 

3.3 

10.49 

0.48 

2.48 

.64 

0.84 

2.7 

0.6 

11.80 

0.57 

2.56 

.71 

0.85 

3.9 

5.3 

10.73 

0.49 

2.48 

.66 

0.82 

3.0 

1.4 

11.11 

0.51 

2.77 

.83 

0.94 

3.4 

4.4 

9.66 

0.43 

2.34 

.58 

0.66 

2.4 

0.7 

15.18 

0.53 

4.16 

3.27 

0.89 

5.6 

2.1 

10.23 

0.53 

2.88 

2.13 

0.75 

3.0 

2.1 

11.79 

0.61 

3.33 

2.47 

0.86 

3.4 

0.6 

18.55 

0.80 

4.81 

3.84 

0.97 

8.4 

0.6 

16.13 

0.68 

3.92 

3.07 

0.85 

6.5 

D.    INFANT  FOODS 

The  markets  are  abundantly  supplied  with  preparations 
known  as  infant  foods,  which,  if  the  statements  of  the 
manufacturers  are  to  be  taken  at  their  face  value,  are 
u 


290 


Principles  of  Human  Nutrition 


remarkably  efficient  for  feeding  young  children.  Without 
question,  these  preparations  have  been  widely  used,  and 
in  many  cases  with  apparently  satisfactory  results.  An 
extended  examination  of  their  sources,  i.e.,  the  raw  mate- 
rials out  of  which  they  are  made,  and  their  chemical  condi- 
tion abundantly  justifies  a  recommendation  of  caution  in 
their  use. 

276.  Composition  of  infant  foods.  —  As  a  means  of  set- 
ting forth  the  real  facts  as  regards  this  class  of  foods, 
reference  is  made  to  the  report  of  an  exhaustive  exam- 
ination in  1908  of  twenty-three  brands.1 

TABLE  LIT 
COMPOSITION  OF  CERTAIN  INFANT  FOODS 


WATER 

S 

PROTEIN 

j 

M 

CARBO- 
HYDRATES 

1 

LACTOSE 

SOLUBLE 
IN  WATER 

STARCH 

Milk  and  Cereals 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Allenbury's  Milk  Food 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

No.  2     

4.98 

3.69 

9.00 

0.28 

68.33 

13.72 

27.14 

82.27 



Horlick's  Malted  Milk 

3  63 

3.70 

12  94 

71.37 

8.36 

0.39 

88.58 

T  ar»fa+orl    TTr^rirl 

7  12 

1  19 

8  13 

82  84 

0.72 

9  67 

34.54 

41  94 

lj£LCt8.teCl  1  OOCl     ... 

Malted  Cereals 

Fessenden's  Food    . 

5.95 

1.60 

6.00 

0.08 

85.97 

0.40 

0.36 

48.80 

35.69 

Mellin's  Infant  Food  . 

5.07 

3.79 

10.50 

0.25 

79.24 

1.15 

0.37 

83.97 



Sunbright's    California 

Baby  Food      .     .     . 

9.00 

1.09 

7.94 

0.22 

81.05 

0.70 

0.19 

6.84 

63.25 

Ridges'  Food      .     .     . 

9.24 

0.60 

11.81 

0.05 

77.26 

1.04 

0.12 

3.90 

69.46 

Miscellaneous 

Peptogenic  Milk  Pow- 

der 

3.02 

1.40 

0.81 

94.67 

0.10 

90.53 

95.40 



Eskay's    Albumenized 

Food      

3.06 

1.34 

6.56 

0.04 

87.80 

1.20 

36.98 

51.10 

28.41 

Conn.  Agric.  Exp.  Station,  Rep.,  1908,  p.  599. 


f  / 


Composition  of  Infant  -Foods 


291 


TABLE  LIII 

SOURCES  AND  INGREDIENTS  OF  CERTAIN  INFANT  FOODS 


WHAT  THE  MANUFACTURERS 
CLAIM 

WHAT  WAS  FOUND 

Allenbury's     Milk 
Fo9<i  No.  2 

Made  from  pasteurized 
rnilk  and  malted  wheat, 
no    unaltered    starch. 
Containing     all      ele- 
ments of  human  milk 
in  natural  proportions. 

No  starch.  Does  not 
contain  elements  of 
human  milk  in  natural 
proportions.  Propor- 
tion of  protein  and  fat 
too  low. 

Horlick's     Malted 
Milk 

Made  from  full  cream 
milk  and  malted  grains. 

No  starch. 

Lactated  Food 

Contains  the  most  im- 
portant elements  of 
mother's  milk,  with  the 
nutritive  principles  of 
the  cereal  grains. 

About  two-fifths  unal- 
tered starch.  Only 
about  one-third  dry 
matter  soluble  in  water. 

Fessenden's    Food 

Made  from  wheat,  rye, 
arrowroot,  and  malted 
barley.  No  cane  sugar 
or  unaltered  starch. 

Raw  arrowroot  starch  ; 
over  one-third  dry 
matter  is  unchanged 
starch.  Less  than  half 
dry  matter  soluble  in 
water. 

Mellin's        Infant 
Food 

Extract  from  wheat  and 
malt.  No  cane  sugar 
or  starch. 

No  starch.  Largely  sol- 
uble in  water. 

Sunbright's     Cali- 
fornia Baby  Food 

A  perfect  modifier  of 
cow's  milk. 

Nearly  two-thirds  dry 
matter  is  unaltered 
starch.  Only  about 
one-seventh  soluble  in 
water. 

Ridges'  Food    .     . 

Baked  flour. 

Largely  raw  wheat  starch. 

Peptogenic      Milk 
Powder 

Chiefly  milk  sugar. 

No  starch.  Mostly  milk 
sugar. 

Eskays'  Albumen- 
ized  Food 

Made  from  egg  albumin 
and  cereal. 

Raw  arrowroot  starch. 
Cooked  cereal  starch. 
Very  little  soluble  pro- 
tein. 

292  Principles  of  Human  Nutrition 

277.  Important   facts   about   infant   foods.  —  The   an- 
alyses quoted  above  reveal  some  facts  that  deserve  careful 
consideration,  which  may  be  summarized  in  the  following 
statements :  — 

I// In  some  brands  the  proportions  of  nutrients  are 
gi^atly  unlike  what  are  found  in  human  milk,  the  protein 
and  fat,  and  sometimes  the  ash,  being  deficient,  and  the 
carbohydrates  greatly  in  excess. 

2^  In  most  cases  the  carbohydrates  are  not  present  as 
lactose,  but  in  part  as  sugar  resulting  from  the  hydrolysis 
of  starch  (probably  glucose)  and  in  part  as  untransformed 
starch. 

3^  In  many  of  the  foods,  a  large  part  of  the  solids  is 
insoluble  in  water,  this  being  true  of  both  protein  and 
carbohydrates. 

278.  Danger  from  unmodified  starch.  —  It  is  clear  that 
the   commercial   infant   foods    are   decidedly   unlike   the 
natural  food  of  the  young  child,  in  one  respect  very  un- 
desirably so.     Reference  is  made  to  the  presence  of  starch. 
When  the  infant  receives  its  natural  food,  there  is  no 
occasion  for  the  exercise  of  the  diastatic  function  in  diges- 
tion (hydrolysis  of  starch  to  sugar),  as  sugar  is  the  only 
carbohydrate  in  milk.     It  was  formerly  held  that  the  very 
young  infant  is  not  able  to  digest  starch  at  all,  but  recent 
investigations  throw  doubt  on  the  accuracy  of  this  con- 
clusion.    Even  if  starch  is  more  or  less  acted  upon  by  the 
young  child,  it  is  an  unnatural  demand  in  the  earliest  stage 
of  development,  and  the  presence  in  the  digestive  tract  of 
so  much  insoluble  material,  not  only  starch  but  proteins,  is 
likely  to  be  attended  with  disorders  of  the  stomach  and 
intestines.     This  would  be  especially  true  of  the  heated 


Feeding  the  Child  293 

season.  German  statistics,  previously  cited  as  to  the  use 
of  cow's  milk,  show  a  still  greater  per  cent  of  mortality 
among  infants  fed  with  these  artificial  preparations.  In 
addition  to  the  unnatural  substitution  of  starch  for  the 
milk  sugar  that  is  in  the  child's  natural  food,  there  is 
also  the  deficiency  in  the  proportions  of  ash  and  fat  to  be 
considered,  a  condition  which  may  easily  have  a  serious 
influence  upon  the  child's  nutrition  and  the  character  of 
its  growth.  Such  a  defiance  of  the  natural  methods  is 
excusable  only  in  cases  of  necessity. 

279.  Standard  for  infant  foods.  —  The  following  stand- 
ard for  infant  foods  quoted  by  Wiley  from  the  British 
Food  Journal  is  worthy  of  attention: 

Definition  :  Infant's  food  is  food  described  or  sold  as 
an  article  of  food  especially  suitable  for  infants  of  twelve 
(12)  months  of  age  or  under. 

Standard  :  Infant's  food  shall  contain  no  woody  fiber, 
no  preservative  substance,  and  no  mineral  substance  in- 
soluble in  acid;  and,  unless  described  or  sold  specifically 
as  food  suitable  only  for  infants  over  the  age  of  six  (6) 
months,  shall,  when  prepared  as  directed  by  any  accom- 
panying label,  contain  no  starch,  and  shall  contain  the 
essential  constituents  of,  and  conform  approximately  in 
proportional  composition  to,  normal  mother's  milk. 

E.    FEEDING  THE  CHILD  AFTER  IT  HAS  PASSED  THE 
PERIOD  OF  INFANCY 

280.  Introduction  of  solid  food  into  diet.  —  The  child's 
nutrition  gradually  passes  from  an  exclusive  milk  diet  to 
one  that  is  in  part  solid  food.     It  is  well  for  the  develop- 
ment of  the  capacity  for  digestion  that  the  admission  of 


294  Principles  of  Human  Nutrition 

solid  food  be  not  too  long  delayed.  Following  weaning  the 
food  will,  for  some  time,  continue  to  be  largely  liquid, 
preferably  cow's  or  goat's  milk,  or  if  necessary  an  infant 
food.  The  latter  should  be  selected  at  first  somewhat 
with  reference  to  its  composition  and  solubility,  the  pres- 
ence of  a  desirable  proportion  of  ash  and  protein  and  the 
absence  of  a  large  proportion  of  unmodified  starch  being 
essential  points  to  consider.  At  eight  to  ten  months  a 
beginning  may  be  made  with  solid  food,  and  for  this  pur- 
pose there  is  nothing  better  than  property  cooked  egg 
(without  leathery  coagulation  of  the  white),  especially  if 
a  cereal  food  is  the  main  part  of  the  diet.  As  the  child 
develops,  milk  should  be  eaten  freely,  and  there  may  be 
added  thoroughly  cooked  cereal  preparations,  crackers, 
stale  bread,  and  so  on  gradually  to  the  same  plain  foods 
that  are  eaten  by  adults. 

281.  Simple  diet  best.  —  For  a  few  years,  mothers 
should  rigidly  adhere  to  the  policy  of  a  simple  diet  from 
which  is  excluded  pastry,  cakes,  sweets,  condiments,  in- 
deed all  desserts  that  generally  are  nutritively  one-sided 
preparations  which  tempt  the  palate  to  the  exclusion  of 
simpler  and  better  balanced  materials.  No  more  serious 
mistake  can  be  made  than  to  allow  a  child  to  acquire  a 
distaste  for  plain  food  because  of  indulgence  in  desserts 
that  are  usually  highly  flavored  and  attractive  to  the 
taste.  The  result  is  that  unless  controlled,  the  child 
discards  the  simpler  foods  best  calculated  to  promote 
vigorous  growth,  and  substitutes  preparations  that  carry 
large  proportions  of  starch,  sugar,  and  fat.  There  is  much 
to  commend  the  practice  of  a  separate  table  for  the  children 
in  the  nursery,  where  temptation  is  out  of  reach. 


Children's  Dietaries  295 

IF  This  habit  of  simple  living  on  meats  in  very  moderate 
proportion,  eggs,  milk,  cereal  foods  (from  the  whole  grain) , 
vegetables,  and  fruits,  with  a  very  small  minimum  of  the 
usual  desserts,  may  well  continue  through  all  the  growing 
^period  and  become  a  life  habit. 

282.  Mixed  diet  desirable.  —  A  fairly  well  mixed  diet 
should  be  encouraged.     While  individual  tastes  cannot 
always  be  overcome  by  education,  an  exclusiveness  of  diet 
on  the  part  of  a  boy  or  girl,  such  as  relative  excess  of  meat 
or  bread  and  butter,  or  even  milk,  should  be  discouraged, 
and  every  effort  made  to  include  in  the  menu  a  reasonable 
proportion  of  vegetables  and  well  ripened  fruits,  without 
neglecting  the  more  substantial  foods. 

283.  The  candy  habit.  —  One  parental  weakness  can- 
not be  too  strongly  condemned,  i.e.,  permitting  a  child  to 
acquire  the  candy  habit.     It  is  true  that  pure  candy  is 
made  of  sugar,  which,  under  right  conditions,  may  play  an 
important  part  in  the  animal  economy.     But  sugar  of  itself 
exercises  no  constructive  function,  and  when  the  free  use 
of  sweetmeats  is  permitted,  generally  at  all  times  of  the 
day,  a  desire  for  wholesome  food  is  much  lessened,  and  the 
child  is  robbed,  sometimes  disastrously  and  always  unfor- 
tunately, of  the  nutrition  to  which  it  is  entitled.     The 
eating  habits  of  some  children  are  nothing  short  of  abomi- 
nable, and  for  these  habits  parents  are  responsible.     It  is  a 
trite  saying,  but  a  true  one,  that  the  intelligent  farmer's 
calves  and  pigs  are  fed  more  rationally  than  many  children. 

284.  Suggestions   for   children's    dietaries.  —  The   fol- 
lowing is  a  summary  of  a  recent  excellent  pamphlet  on  the 
feeding  of  children  issued  by  Columbia  University.1 

1  "  The  Feeding  of  Young  Children,"  Mary  Swartz  Rose,  Ph.D. 


296  Principles  of  Human  Nutrition 

The  meals  suggested  for  children  of  different  ages  illustrate 
rational  food  combinations. 

\s,  The  cultivation  of  a  rational  appetite  is  part  of  the 
trarmng  of  a  child. 

2,,  Children  should  be  fed  regularly  and  not  too  often. 
The  stomach  should  have  a  chance  to  rest. 

3^x  Children  from  two  to  five  years  of  age  need  four 
meals  a  day,  older  ones  three,  at  fixed  hours. 

^x^Milk  is  the  best  food  for  children  of  all  ages,  either 
as  such  or  cooked  into  cereals,  vegetables,  soup,  junket, 
custard,  and  simple  puddings. 

5.  Well-cooked  cereal  should  be  served  every  day,  but 
without  sugar,  syrup,  or  butter.  Use  cereals  that  are 
made  from  whole  grains. 

&  Use  eggs  freely,  soft-cooked  and  not  fried,  and  in 
simple  cooked  dishes. 

7.  "  Children    cannot  thrive    without  fruit."     Give 
only  ripe  fresh  fruit  in  perfect  condition,  or  that  which  is 
stewed  or  baked. 

8.  Fresh  vegetables  should  be  a  part  of  the  diet,  as 
these  are  rich  in  the  needed  mineral  elements.     A  great 
variety  of  well-cooked  vegetables  may  be  served. 

iL  In  general,  provide  a  plain  fare  of  which  bread 
and  butter,  cereals  and  milk  should  form  a  generous 
part. 

10.  Do  not  give  meat  to  children  under  eight  years  of 
age  when  milk  and  eggs  are  available.  When  meat  is 
allowed,  it  should  be  fairly  free  from  fat. 

\\.  For  desserts  provide  simple  puddings  such  as 
junket,  rice,  tapioca,  or  other  cereal  puddings.  Do  not 
allow  candy,  except  a  small  piece  at  meal  time: 


Children's  Dietaries 


297 


1SL  Cultivate  the  habit  in  the  child  of  drinking  a  liberal 
amount  of  water. 

285.  Illustrative  meals  for  children.  —  The  following 
meals  are  suggested  for  children  of  different  ages  as  illus- 
trating rational  combinations  of  food  : — 

CHILD  2-4  YEARS  OLD 

Breakfast : 

7.30  A.M.    Oatmeal  Mush 
Milk 

Stale  Bread 
Orange  Juice 


Lunch : 

11  A.M. 


1.00  P.M. 


Supper : 
5.30  P.M. 


PROTEIN 
Grams 

47.80 


Milk- 

Stale  Bread 
Butter 

Baked  Potato 
Boiled  Onions 

(Mashed) 
Bread  and  Butter 
Milk  to  Drink 
Baked  Apple 

Boiled  Rice 

Milk 

Bread  and  Butter 

FUEL  VALUE 
Calories 
1313 


COST 
Cents 

0.1377 


Substitutes  or  additions:  — 

For  rolled  oats  or  rice:   other  cereals,  such  as  rolled 
wheat,  wheaten  grits,  farina,  hominy,  and  corn  meal. 

For    orange    juice    and   baked  apple :    prune  pulp 
apple  sauce. 


or 


Principles  of  Human  Nutrition 

For  onions :  spinach,  strained  peas,  stewed  celery, 
carrots,  or  cauliflower  tips. 

An  egg  may  be  added  every  day,  and  should  be  included 
at  least  two  or  three  times  a  week. 

These  changes  will  alter  the  cost  somewhat. 


CHILD  4-8  YEARS  OLD 


Breakfast 


Oatmeal  Mush 
Top  Milk 
Stewed  Prunes 
Toast 
Milk  to  Drink 


Dinner :        Pea  Soup 
Croutons 
Boiled  Onions 
Baked  Potato 
Molasses  Cookies 


Supper :        Cream  Toast 

Rice  Pudding  with 
Milk  and  Sugar 
Milk  to  Drink 

PROTEIN  FUEL  VALUE 

Grams  Calories 

65.4  1892 


COST 
Cents 

0.1496 


Substitutes  or  additions :  — 

For  rolled  oats :  other  cereals,  as  suggested  on  previous 
page. 

For  onions  and  peas :  strained  dried  beans ;  other 
vegetables  carefully  cooked ;  fresh  lettuce. 

For  prunes :  fresh  ripe  apples,  baked  bananas,  other 
mild  fruits  well  cooked. 


Children's  Dietaries  299 

For  rice  pudding:  junkets,  custards,  blanc  manges, 
bread  puddings,  and  other  very  simple  desserts. 

For  cookies :  gingerbread,  sponge  cake,  or  very  plain 
cookies. 

CHILD  8-12  YEARS  OLD 

Breakfast:  Oatmeal  Mush 
Top  Milk 
Stewed  Prunes 
Toast 
Milk  to  Drink 

Luncheon :  Pea  Soup 

Boiled  Onions 
Baked  Potato 
Bread  and  Butter 
Molasses  Cookies 

Dinner :       Baked  Haddock 

Creamed  Hashed  Potato 
Spinach 

Bread  and  Butter 
Rice  Pudding  —  Milk 
and  Sugar 

PROTEIN  FUEL  VALUE  COST 

Grams  Calories  Cents 

86.44  2420  0.1875 


Substitutes  or  additions:  — 

For  rolled  oats;  other  cereals  thoroughly  cooked. 

For  haddock:    rare   beefsteak,  roast  beef  or  mutton 
chops;  other  fish,  especially  white  varieties. 

For  prunes:  any  mild  ripe  fruit  uncooked  or  cooked. 

For  onions:  string  beans,  stewed  celery,  beets,  squash. 

Peas  or  spinach:  turnips  or  cauliflower. 


300  Principles  of  Human  Nutrition 

SUGGESTIVE  DIETARY  FOB  CHILD  WHO  WILL  NOT  DRINK  MILK, 
AGE  5  YEARS 

(1  quart  of  milk  concealed  in  the  menu) 

Breakfast : 

7  A.M.  Oatmeal 

Creamy  Egg  on  Toast 
Cocoa 

10  A.M.  Zwieback  and  Cream 

1.30  P.M.    Spinach  Soup 

Baked  Potato  with  Cream 
Bread  and  Butter 
Caramel  Junket 

5.30  P.M.    Rice  and  Prunes 
Zwieback 

PROTEIN  FUEL  VALUE  COST 

Grams  Calories  Cents 

51.9  1431  0.1570 


CHAPTER  XV 

THE    CHARACTER    AND     FOOD     VALUE    OF 
CERTAIN  COMMERCIAL  ARTICLES 

WITHIN  the  last  three  or  four  decades  proprietary  articles, 
either  real  or  so-called  foods,  have  been  offered  to  the  public 
in  greatly  increasing  numbers.  These  have  very  properly 
received  special  consideration  for  two  reasons,  (1)  ii 
many  instances  remarkable  but  utterly  unfounded  claims 
have  been  made  for  their  nutritive  value,  thereby  deceiving 
an  undiscriminating  public,  and  (2)  the  general  high  cost 
of  a  unit  of  nutritive  value  in  them  as  compared  with  home 
preparations  of  equal  or  greater  nutritive  efficiency.  No 
more  striking  examples  of  deceptive  or  even  utterly  false 
statements  and  of  bad  business  ethics  are  to  be  found  than 
are  shown  in  the  exploitation  of  some  of  these  articles. 

A.    MEAT  PREPARATIONS,  EXTRACTS,  FLUID  EXTRACTS, 
MEAT  JUICES 

286.  True  meat  extract.  —  In  order  to  judge  intelli- 
gently the  commercial  meat  extracts  as  they  actually 
are,  we  should  first  consider  what  a  real  meat  extract  is. 
The  manufacture  of  these  preparations  was  greatly 
promoted  by  Baron  von  Liebig's  researches  on  the  chem- 
istry r "  meat,  although  something  similar  had  been  used 

301 


302  Principles  of  Human  Nutrition 

for  many  years  before.  The  original  Liebig  method  of 
making  the  extract  is  to  treat  finely  chopped  beef  with 
eight  times  its  weight  of  cold  water,  thus  dissolving  only  a 
very  small  part  of  the  beef,  the  substances  taken  into 
solution  being  ash  compounds,  chiefly  potassium  phos- 
phate, some  albumin  and  the  extractive  creatin  and  its 
anhydride  creatinin.  The  liquid,  after  being  strained 
from  the  beef,  is  heated  sufficiently  to  coagulate  the  al- 
bumin, this  coagulum  is  filtered  off,  and  the  remaining 
extract,  containing  the  ash  compounds  and  extractives,  is 
evaporated  to  a  paste.  While  popularly  regarded  as  such, 
this  preparation  can  hardly  be  considered  as  a  food,  for,  as 
previously  stated,  the  beef  extractives  creatin  and  creatinin 
.furnish  to  the  body  neither  constructive  material  nor 
energy,  but  are  largely  eliminated  in  the  urine  unchanged 
(see  p.  61).  These  bodies-  impart  a  flavor  to  cooked 
beef,  and  besides  have  the  important  function  of  vigor- 
ously exciting  the  secretion  of  gastric  juice  (see  Chap.  V, 
p.  100).  One  author  (Hutcbinson)  truly  says  of  them 
that,  "  They  are  thus  eminently  calculated  to  rouse 
appetite  and  aid  the  digestion  of  any  food  with  which 
they  may  be  taken.  This,  indeed,  is  their  true  function-1 
both  in  health  and  disease.  They  are  flavoring  agents, 
and  their  proper  place  is  in  the  kitchen  and  not  by  the 
bedside."  l 

287.  Commercial  meat  extracts.  —  The  foregoing  are 
the  specifications  of  a  true  beef  extract  as  defined  by 
Liebig.  It  is  interesting  to  note  what  is  the  real  character 
of  the  extracts  now  in  the  market,  for  which  surprising 
claims  are  made.  In  1908,  the  Connecticut  Agricultural 

1  "  Food  and  Dietetics,"  Hutchinson,  p.  93. 


Commercial  Meat  Extracts  303 

Experiment  Station 1  made  an  exhaustive  examination  of 
twenty-two  brands  of  meat  extracts,  twenty-three  brands 
of  fluid  and  semi-fluid  preparations,  and  four  brands  of 
meat  juices.  Of  these  47  preparations  10  were  found  to  be 
properly  branded  and  up  to  the  standards,  17  were  found 
to  be  misbranded  and  varying  from  the  standards,  and  the 
others  were,  in  general,  not  up  to  the  standards,  though  not 
misbranded.  The  standards  with  which  the  preparations 
were  compared  are  those  based  on  analyses  of  genuine 
beef  extracts.  The  misbranding  consisted  in  such  mis- 
leading or  false  statements  as  the  following :  "  no  foreign 
matter,"  "  absolutely  unadulterated,"  when  a  large 
quantity  of  salt  had  been  added,  "  the  nutritious  portion 
of  beef  in  concentrated  form,"  "  a  concentrated  food  that 
represents  the  nourishing  constituents  of  fresh  beef,"  "  all 
that  is  nourishing,  sustaining  and  palatable  in  fresh  beef," 
"  a  combination  of  all  the  strengthening  and  stimulating 
properties  of  prime  lean  beef,"  "  the  most  perfect  form  of 
concentrated  food  known,"  "  pure  essence "  of  beef, 
statements  that  deceive  the  uninformed,  because  these 
materials  are  not  concentrated  foods  and  can  by  no  possi- 
bility contain  more  than  a  very  small  part  of  the  nutriment 
of  beef.  There  is  no  such  thing  as  concentrating  the  nutri- 
tive constituents  of  beef,  except  by  drying  out  the  water, 
for  practically  all  the  dry  matter  of  clear  lean  beef  is 
digested,  and  all  of  it  is  nutritious.  When  beef  extract  is 
made,  the  major  portion  of  the  beef,  indeed,  nearly  .all 
its  nutritive  value,  is  rejected.  Attention  should  be 
called  to  the  very  high  cost  of  the  dry  organic  matter  in 
these  extracts.  It  was  found  that  the  22  meat  extracts 

i  Rep.,  1908,  pp.  606-664. 


304  Principles  of  Human  Nutrition 

contained  from  14.8  to  40.4  per  cent  of  water,  from  17.6 
to  35  per  cent  of  ash,  largely  common  salt,  and  37.3  to 
67.6  per  cent  of  organic  matter.  The  prices  of  packages 
varying  in  weight  from  1.4  to  3.4  ounces  ranged  from  15  to 
50  cents.  The  least  cost  per  pound  of  dry  matter  was  $1, 
and  the  greatest  $5.70,  the  dry  organic  matter  costing 
from  $2.68  to  $10.18  per  pound.  Beef  tea  and  beef  juice 
made  at  home  are  as  good  as  or  better  than  these  prepara- 
tions, and  cost  greatly  less.  The  trade  in  some  of  these 
extracts  is  a  fraud  on  the  consumer. 

B.    BREAKFAST  FOODS 

288.  Sources  and  kinds.  —  The  so-called  breakfast 
foods  are  sold  under  a  great  and  steadily  increasing  variety 
of  names  and  forms.  They  are  extensively  used,  being 
now  found  on  the  table  of  nearly  every  family  of  well-to- 
do  communities.  (The  sources  from  which  they  are  derived 
are  the  cereal  grains,  corn,  oats,  wheat^  There  are  three 
general  methods  of  preparation:  (rLgrinding  the  decor- 
ticated grain,  (2)^  steaming  or  otherwise  cooking  with 
subsequent  grinding  or  rolling,  and  J^  malting,  that 
is,  the  production  of  materials  in  which  the  starch  has 
been  partially  changed  to  a  soluble  form  by  the  action  of 
heat  or  diastase.  It  should  be  stated  that  these  foods  do 
not  receive  special  mention  because  of  inferior  quality. 
They  appear  to  be  prepared  in  a  hygienic  manner,  are  not 
adulterated,  are  so  thoroughly  dried  as  to  keep  well,  and, 
in  general,  may  be  considered  to  be  among  the  very  best 
of  the  foods  carrying  a  high  proportion  of  carbohydrates. 
It  is  the  claims  that  are  made  for  such  extensively  used 
materials,  and  the  wide  differences  in  their  cost,  that  render 


Breakfast  Foods 


305 


it  advisable  to  consider  the  real  facts  touching  their  nutri- 
tive value. 

289.  Composition.  —  The  composition  of  these  foods 
is  found  to  be  similar  to  that  of  the  grains  from  which  they 
are  made.  The  following  table  will  bear  careful  study  on 
this  point. 

TABLE  LIV 

AVERAGE  COMPOSITION  OF  CEREAL  BREAKFAST  PREPARATIONS 
COMPARED  WITH  WHEAT  FLOUR  VARIOUSLY  MlLLED l 


h 

55 

K  » 

te 

5 

ft  * 

SI 

W   IH 

1 

| 

Sj 

«  < 

I 

H  g 

P 

1 

3g 

< 

EC 

Per 

Per 

Per 

Per 

Per 

Calories 

14 

Corn  meal  and  hominy 

Cent 

Cent 

Cent 

Cent 

Cent 

Gram 

(uncooked)     .     .     . 

10.7 

8.6 

0.7 

79.7 

0.3 

3.854 

28 

Rolled  oats  (cooked)  . 

8.4 

15.6 

7.5 

66.6 

1.9 

4.323 

35 

Rolled  wheat  (cooked) 

9.9 

12.0 

1.9 

74.8 

1.4 

3.966 

1 

Malted  oats  (cooked). 

6.4 

16.7 

5.4 

69.7 

1.8 

4.318 

4 

Malted  wheat  (cooked) 

6.9 

13.3 

1.2 

77.0 

1.6 

4.017 

4 

Graham  flour     .     .      . 

10.7 

14.8 

2.3 

70.3 

1.9 

4.029 

4 

Entire  wheat  flour 

11.4 

14.1 

2.0 

71.5 

1.0 

3.967 

4 

Standard  patent  flour 

11.4 

13.9 

1.4 

72.8 

0.5 

3.959 

290.  Changes    in    preparation.  —  In    the   cooked  and 
malted  foods,  the  starch  has  been  more  or  less  changed  to 
other  carbohydrates,  mostly  dextrin  (see  Table  LV). 

291.  Digestibility.  —  As  the  processes  of  manufacture 
have  not  rendered  these  preparations  greatly  unlike  the 
cereal  grains  in  which  they  have  their  source,  except  in 
some  of  them  to  dextrinize  part  of  the  starch,  we  must 
look   to   their   digestibility   for   any   increased   nutritive 
efficiency  which   they  may  possess.     The  most  reliable 

1  Maine  Agric.  Exp.  Station,  Bui.  118,  p.  121. 


306 


Principles  of  Human  Nutrition 


TABLE    LV 

RELATIVE  PERCENTAGES  OP  STARCH  AND  DEXTRIN  IN  CERTAIN 
CEREAL  BREAKFAST  FOODS  l 


STARCH 

DEX-EBIN 

EXTENT  OF 
DEXTRINIZATION 

Per  Cent 
6Q  ^ 

Per  Cent 

Per  Cent 

Oat  meal 

63  8 

Rolled  oats    

60.5 

3.6 

56 

Ralston  breakfast  food    . 
Malt  breakfast  food   .     . 

67.9 
71.7 
62.4 

2.6 
3.2 
9.3 

3.7 
4.3 
130 

Force 

554 

145 

20  7 

Grape  Nuts  

49.5 

249 

33  5 

TABLE    LVI 
COMPARATIVE  DIGESTIBILITY  OF  CEREAL  FOODS 


« 

j  2  a 

5 

M  * 

is 

ft!   ^ 

^  5  £"* 

H 

OH 

5 

*~  C£ 

G< 

00%, 

O 

CQ  <• 

d  g 

•"!  Q 

0 

•< 

Per  Ct. 

Per  Ct. 

PerC  . 

Per  Ct. 

Per  Ct. 

Per  Ct. 

Rolled  oats  (simple  diet)     .     . 



95.4 

84.7 





94.2 

Rolled  wheat  (simple  diet) 



95.2 

91.6 





94.6 

Force  (simple  diet)      .... 



94.6 

89.6 





91.1 

Grape  nuts  (simple  diet)      .     . 



94.0 

87.6 





93.1 

Shredded  whole  wheat  (simple 

diet)      



92.8 

84.1 

— 



91.4 

Hecker's  hominy  (simple  diet) 



97.3 

83.6 





96.4 

Granulated  corn  meal    (simple 

diet)      



97.2 

82.3 





95.9 

Hulled  corn  (eaten  alone)    .     . 





81.7 

97.3 



91.8 

Wheat  bread  (eaten  alone) 





93.9 

99.1 



97.3 

Johnny  cake  (simple  diet)  . 





93.2 

98.9 



93.5 

Brown  bread  (simple  diet) 





92.8 

98.6 



93.4 

1  Maine  Agric.  Exp.  Station,  Bui.  118,  p.  126. 


Breakfast  Foods  307 

figures  available  do  not  show  that  breakfast  foods  differ 
essentially  in  digestibility  from  cereal  flours  and  meals, 
and  certain  home-made  preparations.  The  figures  given 
in  Table  LVI,  as  well  as  those  in  the  two  previous  tables  are 
largely  the  result  of  work  done  at  the  Maine  Agricultural 
Experiment  Station,  with  others  quoted  by  Atwater. 

The  digestibility  of  breakfast  foods  is  proved  to  be  in 
no  respect  superior  to  that  of  granulated  corn  meal, 
johnny  cake,  brown  bread,  or  white  bread. 

292.  Unwarranted  claims.  —  It  is  clear  that  the  claims 
made  for  certain  breakfast  foods,  such  as  the  nourishing  of 
more  persons  for  a  given  time  than  other  foods  do,  "  the 
most  natural  food  for  mankind/'  "  the  great  brain  and 
muscle  food,"    "a   condensed  food,"    "the.  system  will 
absorb  a  greater  amount  of  nourishment  from  one  pound  of 
than  from  ten  pounds  of  meat,  wheat,  oats  or  bread," 
are  false,  and  the  manufacturers  making  these  claims  either 
intend  to  deceive  the  public  or  are  grossly  ignorant  of  the 
real  nutritive  value  of  their  products.     The  fact  is,  it  is 
not  possible  so  to  transform  the  nutrients  in  meats  and 
cereal   grains   as   materially   to   enhance   their  nutritive 
efficiency,  nor  can  such  foods  be  "  condensed,"  excepting  as 
water  is  dried  out.     Cooking  and  malting  may  increase  the 
ease  and  rapidity  of  digestion,  but  for  persons  normal  in 
health  and  function  there  is  nothing  in  the  processes 
applied  to  breakfast  foods  superior  in  any  respect  to  home 
cooking. 

293.  Money  cost.  —  We  can  now  consider  intelligently 
the  cost  of  breakfast  foods,  for  this  is  practically  the  only 
question  the  housewife  needs  to  raise.     The  pound  cost 
of  such  foods  varies  greatly,  ranging  from  four  cents  to 


308 


Principles  of  Human  Nutrition 


approximately  25  cents.  In  1908  the  average  cost  in  a 
New  England  market  for  the  various  classes  was  as  fol- 
lows, when  purchased  in  packages :  — 

TABLE    LVII 

MAXIMUM,  MINIMUM,  AND  AVERAGE  COST  PER  POUND  OP 
WHEAT,  OAT,  AND  CORN  BREAKFAST  FOODS  PURCHASED  IN 
PACKAGES l 


PRICE  PER  POUND 

NUMBEK  OF 

KIND  OP 

SAMPLES 

CEREAL 

I 

•    Maximum 

Minimum 

Average 

Cents 

Cents 

Cents 

24 

Wheat     .     . 

11.4 

4.9 

7.8 

17 

Oats  .     .     . 

7.8 

4.1 

6.0 

10 

Corn  .     .     . 

9.2 

4.1 

5.5 

By  use  of  the  foregoing  figures  it  is  easy  to  calculate 
the  nutrition  that  could  be  bought  for  one  dollar.2 

TABLE   LVIII 
NUTRITION   PURCHASED  FOR  ONE  DOLLAR 


*«« 

K 

H  « 

O  O  j 

^ 

LM 

fe  2 

II 

g  g  0 

\ 

H 

ffl  ^ 

W 

Is- 

III 

£ 

J§ 

la 

Ko 

Cents 

Lb. 

Lb. 

Lb. 

Lb. 

Cal. 

Rolled  wheat     .     .     . 

7.8 

12.8 

1.54 

0.24 

9.57 

0.18 

40.3 

Rolled  oats  .... 

6.0 

16.7 

2.79 

0.90 

11.64 

0.30 

72.0 

Hominy    

5.5 

18.2 

1.56 

0.13 

14.50 

0.05 

70.2 

Patent  flour       .     .     . 

3.5 

28.6 

3.98 

0.40 

20.82 

0.14 

113.2 

1  Including  only  the  hominies. 

2  Maine  Agric.  Exp.  Station,  Bui.  118,  pp.  132,  133. 


Alcohol  in  Nutrition  309 

It  should  be  noted  that  when  some  of  these  foods  are 
bought  in  bulk,  the  cost  is  less  than  the  above  averages, 
not  exceeding  four  cents  per  pound.  In  view  of  their 
ease  of  preparation,  with  the  saving  of  fuel  and  labor,  they 
may  be  economical  when  so  purchased,  as  compared  with 
the  common  raw  materials,  such  as  flour  and  the  meals, 
which  can  be  bought  at  from  two  to  three  cents  per  pound. 

C.    ALCOHOL  IN  NUTRITION 

Immense  quantities  of  alcohol  are  consumed  by  the 
human  family  in  such  beverages  as  koumis,  kephir,  beers, 
wines,  and  the  strong  drinks,  whiskey,  brandy,  gin,  and 
rum,  the  intemperate  drinking  of  many  of  which  has 
caused  untold  degradation  and  misery.  The  sentimental 
and  moral  considerations  that  relate  to  the  use  of  alcohol 
in  all  forms  have  led  to  absurd  and  grossly  inaccurate 
teachings  concerning  its  real  physiological  functions  and 
reactions. 

294.    Alcohol  is  oxidized  in  body.  —  Until  the  applica- 
tion of  exact  measurements,  it  was  held  that  alcohol  is 
largely  excreted  from  the  body  as  such,  and  performs  no 
useful  physiological  service.     It  is  now  definitely  proven 
that  with  the  moderate  use  of  alcohol  only  a  very  small 
proportion  is  given  off  in  the  breath  and  urine,  perhaps  not 
more  than  2  per  cent.     More  than  this,  it  is  demonstrated  ] 
beyond  question  that  alcohol,  when  taken  up  to  2j  ounces  i 
per  day,  at  least,  is  almost  wholly  oxidized,  and  serves  thej 
human  organism  as  a  source  of  energy.     Moreover,  up  tol 
a  limited  extent,  it  will  replace  such  nutrients  as  sugarj 
and  starch.     When  in  experiments  by  Atwater  and  Bene- 
dict 72  grams  (about  2j  oz.)  of  alcohol  was  substituted  for 


Principles  of  Human  Nutrition 


an  isodynamic  (equivalent  in  energy)  amount  of  sugar,  the 
results  in  heat  production  and  body  storage  were  exactly 
the  same. 

The  figures  of  the  following  table1  showing  the  results  of 
five-day  periods  of  observation  of  a  man  in  a  respiration 
calorimeter  are  a  convincing  demonstration  of  the  fore- 
going statements :  — 

TABLE   LIX 
USE  OF  ALCOHOL 


INTAKE 

METAB- 

BALANCE 

RETEN- 

OLISM 

TION  IN 

SERIES 

CAL- 

CAL- 

Diet 

Calories 

ORIES 

Proteid 

Fat 

ORIES 

Grams 

Grams 

23 

Fixed  diet      

=2546 

2176 

-1.6 

+  9.0 

77 

22 

Fixed  diet  +  72  grams  alco- 

hol (  =  500  calories)      .     . 

=3044 

2258 

+1.4 

+62.7 

589 

24 

Fixed  diet  +  130  grams  sugar 

(  =  515  calories  .... 

=3061 

2272 

+1.7 

+59.7 

56 

22-23 

Difference      

=  498 

+82 

+3.0 

+53  7 

=  512 

24-23 

Difference 

-  515 

+96 

+3  3 

+50  7 

=485 

24-22 

Difference 

=     15 

+14 

+0.3 

-  3.0 

=  -27 

It  appears  not  only  that  72  grams  of  alcohol  took  the 
place  of  130  grams  of  sugar,  but  that  the  use  of  protein 
was  not  unfavorably  affected. 

295.  Relation  to  muscular  effort.  —  It  should  not  be 
assumed  from  the  above  data  that  alcohol  may  serve  as 
a  direct  source  of  muscular  effort.  It  is  true,  however, 
that  when  in  the  diet  of  men  at  work  fat  has  been  replaced 


1  "  Metabolism  and  Practical  Medicine,"  Von  Noorden,  Vol.  1,  p.  350. 


Alcohol  Not  a  Necessary  Food  311 

by  its  energy  equivalent  of  alcohol,  and  the  work  performed 
has  not  changed,  the  total  output  of  heat  has  been  no  greater 
than  on  an  alcohol-free  diet.  This  may  be  explained  on 
the  ground  that  the  alcohol  spared  the  use  of  the  carbohy- 
drates in  some  other  direction  than  muscular  effort.  It 
should  be  understood  that  these  conclusions  do  not  apply 
to  the  use  of  alcohol  in  quantities  that  are  toxic  and  disturb 
the  normal  physiological  processes.  Nor  is  it  argued  that 
it  is  desirable  or  necessary  to  use  alcoholic  beverages. 
Indeed,  the  advice  is  rather  to  let  these  drinks  alone. 

296.  Alcohol  not  a  necessary  food.  —  It  is  sometimes 
ignorantly  asserted  by  individuals  who  have  acquired  an 
alcohol  habit  that  it  is  a  physiological  necessity  for  them. 
Alcohol  is  never  physiologically  necessary  for  any  normal 
human  organism,  and  in  health  there  is  no  advantage  in 
its  use.  The  exhilaration  due  to  taking  beer  and  wine  or 
stronger  drinks  is  not  an  evidence  of  physiological  benefit. 
Another  foolish  belief  is  that  alcoholic  liquors  are  a  defense 
against  cold.  The  sensation  of  warmth  following  a  drink 
of  whiskey  is  due  to  an  increased  flow  of  blood  to  the  sur- 
face of  the  body.  This  does  not  conserve  body  heat,  but 
rather  the  reverse.  Patent  medicines  containing  alcohol 
often  get  a  reputation  for  curative  properties  when  the 
alleged  benefits  are  nothing  more  than  a  temporary  exhilara- 
tion. Notwithstanding  all  these  errors  that  are  believed, 
nothing  is  gained  in  the  way  of  physiological  welfare  and 
temperance  by  ungrounded  assertions  as  to  the  dire  results 
of  taking  a  little  alcohol  into  the  stomach. 


CHAPTER  XVI 
THE  PREPARATION  OF  FOOD 

THE  variety  of  food  preparations  that  are  served  on  the 
tables  of  well-to-do  families  is  almost  endless  in  number, 
and  human  ingenuity  seems  to  be  exercised  to  the  limit  in 
devising  new  ones.  It  is  no  exaggeration  to  declare  that 
we  are  now  living  in  a  period  of  gastronomic  luxury  that 
makes  heavy  demands  on  both  our  financial  and  physical 
resources.  It  is  not  possible  to  deal  with  the  recipe 
phase  of  cookery,  excepting  within  the  limits  of  a  "  cook 
book."  There  are,  however,  general  principles  pertaining 
to  all  cookery  that  may  properly  be  discussed  in  this  con- 
nection. The  preparation  of  food  may  be  considered  from 
several  points  of  view,  viz.  the  chemical  reactions  produced 
by  certain  combinations,  the  effects  of  cooking,  special 
considerations  pertaining  to  classes  of  foods,  and  mechani- 
cal display. 

A.  CHEMICAL  REACTIONS    OR  CHANGES  DUE    TO   SPE- 
CIFIC CAUSES 

The  chemical  reactions  that  need  to  be  considered  under 
this  head  are  the  evolution  of  carbonic  acid  for  lightening 
bread  and  cake,  and  the  action  of  acids  upon  coagulable 
proteins. 

297.  The  evolution  of  carbonic  acid.  —  This  is  done  in 
order  to  lighten  the  texture  of  bread  and  cake,  and  is  \ 

312 


Chemical  Changes  313 

/brought  about,  excepting  in  yeast  fermentation,  by  the 
[reaction  of  some  acid  or  acid  salt  on  a  bicarbonate  of 
^either  sodium  or  potassium,  generally  the  former.  In  old- 
fashioned  cooking,  sour  milk  and  "  saleratus  "  (potassium 
bicarbonate)  were  used  in  making  "  saleratus  biscuit." 
In  this  case,  the  carbonic  acid  was  displaced  in  the  sal- 
/eratus  by  the  action  of  the  acids  or  acid  salts  in  the  milk, 
'.forming  little  vesicles  of  gas  all  through  the  dough,  thus 
greatly  lightening  its  texture.  When  soda  (sodium  bi- 
carbonate) is  added  to  dough  sweetened  with  molasses, 
the  same  result  is  reached  because  of  the  acid  substances 
in  the  molasses.  In  order  that  there  may  be  no  excess  of 
soda  or  acid,  it  is  necessary  that  they  be  combined  in  defi- 
nite proportions.  In  home  cookery,  where  sour  milk  and 
molasses  are  used,  the  'combination  is  more  or  less  "  hit 
or  miss  "  for  the  acidity  of  these  materials  is  not  always  the 
same.  When  the  acids  are  in  excess  rather  than  the  soda, 
the  results  are  not  serious,  as  is  the  case  when  too  much 
soda  is  used.  At  the  present  time  "  baking  powders  " 
are  in  the  market,  in  which  the  combinations  are  chemically 
correct. 

298.  The  coagulation  of  proteins.  —  The  housewife  of 
experience  does  not  need  to  be  reminded  that  vinegar 
and  milk  do  not  always  constitute  a  compatible  mixture, 
as  the  casein  of  the  milk  sometimes  precipitates  or  forms  a 
curd.  /The  same  change  sometimes  takes  place  when 
milk  is  improperly  added  to  tomato  soup.  The  results 
with  vinegar  and  milk,  that  is,  acetic  acid  and  the  calcium 
casein,  depend  upon  the  proportion  of  acid  to  casein. 
The  curdling  of  the  milk  is  due  to  the  fact  that  the  acid  of 
the  vinegar  removes  the  lime  from  its  combination  with 


314  Principles  of  Human  Nutrition 

the,  casein ;  but  precipitation  of  the  casein  does  not  begin 
until  the  amount  of  acid  passes  a  certain  proportion. 
Probably  one  half  ounce  of  4  per  cent  vinegar  could  be 
added  to  one  quart  of  milk  without  causing  curdling 
when  the  milk  is  heated  to  boiling,  but  much  beyond  this 
proportion  would  precipitate  the  casein.  At  ordinary 
temperatures  much  more  vinegar  would  be  used,  perhaps 
two  ounces.  The  proportion  of  vinegar  would  depend 
on  its  strength,  of  which  the  housewife  is  not  generally 
informed,  an  example  of  the  inexact  way  in  which  much 
cooking  is  necessarily  done.  The  same  considerations 
apply  to  the  use  of  milk  with  acid  materials,  such  as 
fruits  containing  citric,  tartaric,  or  malic  acids.  The 
condition  of  the  milk  is  to  be  considered,  too.  Fresh 
milk  will  bear  more  acid  than  milk  in  which  more  or1 
less  lactic  acid  has  developed  and  combined  with  part  of' 
the  lime  in  the  casein  compounds. 

When  meat  proteins  and  the  white  of  egg  are  cooked, 
coagulation  occurs,  with  a  hardening  of  the  meat  tissue 
and  of  the  egg  albumin.  This  is  discussed  more  fully  in 
what  follows. 

B.  THE  EFFECT  OF  COOKING,  OR  THE  ACTION  OF 
HEAT  UPON  FOODS  IN  ROASTING,  FETING,  BAKING, 
AND  BOILING 

299.  Effect  of  cooking  on  tissues.  —  All  methods  of 
applying  heat,  whether  dry  or  wet,  modify  the  mechanical 
condition  of  raw  foods.  Both  dry  and  wet  heat  harden  thte 
tissues  of  meat,  and  wet  heat,  or  boiling,  disintegrates  th<i 
fibers,  softens  the  connective  tissue,  and  renders  the  meat 


Effects  of  Cooking,  —  Losses  315 

[more  easily  masticated.  In  the  case  of  cereals,  whether 
with  dry  or  wet  heat,  the  starch  grains  that  are  confined 
in  the  vegetable  cells  are  expanded,  and  the  cellulose 
covering  of  the  cells  is  burst,  liberating  the  cell  contents, 
n  the  case  of  boiled  vegetables  their  fiber  is  disintegrated, 
the  contents  of  the  cells  are  more  or  less  liberated,  and  the 
tissue  is  rendered  much  more  tender.  Cooking  foods  at 
boiling  temperature  by  any  process  whatever  coagulates 
and  hardens  certain  of  the  proteins  such  as  the  albumin 
and  myosin  of  meat  and  the  white  of  egg.  Boiling  milk 
causes  a  coagulum.  The  same  thing  occurs  to  a  limited 
extent  in  vegetable  foods,  but  the  result  is  not  so  evident. 
/Dry  hfifl.t  converts  starch  into  dextrin,  a  soluble  carbohy- 
fdrate,  as  in  the  brown  crust  of  corn  and  wheat  breads,  the 
Surface  of  toasted  bread  and  of  baked  potatoes.  When 
apples  or  other  fruits  are  baked,  their  tissue  is  gelatinized 
through  the  conversion  by  hydrolysis  of  pectin  into  pec- 
tose.  In  cooking  food  of  whatever  class  by  steaming 
or  boiling,  more  or  less  of  the  soluble  matter  is  ex- 
tracted. 

300.  Losses  in  cooking  meats.  —  The  various  meats 
contain  from  five  to  eight  per  cent  of  soluble  constituents, 
including  ash  compounds,  albumin,  the  extractives  creatin 
and  creatinin,  organic  acids,  glycogen,  inosite,  and  other 
organic  bodies.  When  meat  is  cooked  by  any  method 
whatever,  a  portion  of  these  compounds,  together  with 
some  of  the  fat,  is  taken  into  solution  or  is  found  in  the 
drippings.  At  a  boiling  temperature,  the  collagen  of  the 
connective  tissue  is  changed  to  gelatin,  which  is  soluble 
in  hot  water,  and  assumes  a  semi-solid  state  when  meat 
broth  is  cooled. 


316 


Principles  of  Human  Nutrition 


Extensive  experiments  by  Grindley  *  revealed  the  follow- 
ing losses  from  the  meat  by  the  various  methods  of  cook- 
ing:— 

TABLE    LX 

LOSSES  FROM  MEAT  BY  VARIOUS  METHODS  OF  COOKING 


TEMPER- 

NUTRIENTS  IN  BROTH  OR 
DRIPPING  IN  PERCENT- 

METHOD 

COOKING 

TIME 

AGE  OF  TOTAL  AMOUNTS 
IN  UNCOOKED  MEAT 

KIND  OF  A!EAT 

OF 

OF 

COOKING 

j,   60 

bO 

bO  C 

COOKING 

•**  .9 

•9  3 

Water 

Pro- 
tein 

Fat. 

Ash 

Po 

Per 

Per 

Per 

Per 

°C 

°c 

Hrs. 

Cent 

Cent 

Cent 

Cent 

Beef,  round,  lean 

Boiling 

100 

80-85 

5 

52.7 

8.0 

10.3 

55.4 

Beef,  round,  lean 

Boiling 

100 

80-85 

2j^ 

51.0 

4.9 

5.1 

44.0 

Beef,  round,  lean 

Boiling 

25-25 

80-85 

5 

54.6 

5.3 

14.7 

41.8 

Beef,  round,  lean 

Boiling 

20-25 

81 

2/^ 

53.1 

9.7 

20.7 

54.2 

Beef,     round,     lean, 

large  piece    .     .     . 

Boiling 

100 

80-85 

2 

45.8 

6.3 

6.2 

41.5 

Beef,     round,     lean, 

small  piece  .     .     . 

Boiling 

100 

80-85 

2 

57.0 

8.5 

17.8 

57.2 

Beef,     round,     lean, 

3^-inch  cubes    .     . 

Boiling 

100 

80-85 

2 

60.7 

11.9 

13.4 

61.0 

Beef,    round,    rather 

fat      

Boiling 

100 

80-85 

3 

53.5 

7.4 

22.5 

49.3 

Beef,  round,  lean 

Pan 





15-20 

30.5 

0.16 

0.1 

0.06 

broiling 





min. 

Beef,  round,  lean 

Sauteing 





15 

36.5 

0.46 

3.32 

0.04 

min. 

Beef  riba     .... 

Roasting 

249 

193 

%  to  1% 

33.7 

1.2 

24.7 

15.1 

301.  Relative  loss  from  meats  by  different  methods 
of  cooking.  —  These  data  are  important  because  meats 
are  the  most  costly  part  of  the  family  diet.  The  results 
of  Grindley's  conclusions  are  summarized  in  the  following 
statements  :  — 


Bui.  141,  O.E.S. 


2  Apparent  gain. 


Losses  from  Cooking 


317 


TABLE    LXI 
LOSSES  FROM  VEGETABLES  WHEN  COOKED  IN  VARIOUS  WAYS 


Loss  IN  PER  CENT  OF  TOTAL  AMOUNTS 

KIND 

IN  UNCOOKED  VEGETABLES 

VEGE- 

MANNER OF  TREATMENT 

•f-v__. 

Protein 

Total 

Starch 

TABLE 

JJry 

Matter 

Ni- 

Ni- 

or 

Ash 

trogen 

trogen 

Sugar 

Per 

Per 

Per 

Per 

Per 

Potatoes 

Skins   removed,    soaked   in 

Cent 

Cent 

Cent 

Cent 

Cent 

cold  water  before  cooking. 

Cooking    begun    in    cold 

water 

6.5 

25.0 

51.8 



38.3 

Potatoes 

Skins         removed.         Not 

soaked.     Cooking    begun 

in  cold  water. 

3.1 

7.3 

15.8 

1.0 

18.8 

Potatoes 

Skins         removed.         Not 

soaked.     Cooking    begun 

in  hot  water. 

3.4 

3.2 

8.2 

1.0 

18.0 

Potatoes 

Skins  not  removed.     Cook- 

ing begun  in  cold  water. 

0.4 

0.6 

1.0 

0.1 

3.5 

Potatoes 

Skins  not  removed.     Cook- 

ing begun  in  hot  water. 

0.4 

0.4 

1.0 

0.1 

3.3 

Carrots 

Small  pieces 

29.9 

10.3 

42.5 

26.0 

47.3 

Carrots 

Medium  sized  pieces 

23.5 

6.4 

27.5 

26.5 

37.0 

Cabbage 

Cooking  begun  in  cold  water. 

39.3 

6.7 

39.6 

38.2 

47.06 

Cabbage 

Cooking  begun  in  hot  water. 

35.1 

7.0 

35.8 

34.3 

40.2 

1.  The  chief  loss  in  weight  with  any  method  of  cooking 
is  water,  except  that  in  roasting  much  fat  goes  into  the 
^drippings. 

f  2.  The  smallest  loss  was  in  pan  broiling,  sauteing  caus- 
ing but  little  more.  Much  the  largest  loss  was  by  roasting 
and  boiling,  averaging  the  most  for  fat  in  roasting,  and 
most  for  proteins  (extractives  and  gelatin  largely)  and  ash 
in  boiling. 

3.    The  temperature  of  the  water  into  which  the  meat 


318  Principles  of  Human  Nutrition 

'was  introduced,  whether  boiling  heat  or  68-77°  F,,  seemed 
to  have  little  influence  upon  the  contents  of  the  broth. 

4.  Large  pieces  of  meat  lost  less  relatively  than  small 
pieces. 

5.  The  loss  increased  with  the  time  of  cooking. 

302.  Losses  in  cooking  vegetables.  —  In  cooking  vege- 
tables in  water,  a  much  greater  loss  by  solution  occurs  than 
is  generally  realized.     The  extraction  of  ash  ingredients  is 
especially  large,  and  in  throwing  away  the  water  in  which 
potatoes  and  other  vegetables  are  cooked  a  considerable 
waste  of  nutritive  material  occurs.     The  method  of  pre- 
paring vegetable  food  determines  the  proportion  of  loss. 
Peeling  potatoes,  carrots,  beets,  and  turnips  greatly  increases 
the  loss  as  the  experimental  results  given  in  Table  LXI 
show.1 

303.  Relative  loss  from  vegetables  by  different  methods 
of  cooking.  —  Several  conclusions  are  clearly  warranted 
by  the  foregoing  figures. 

1.  When  potatoes  with  their  skins  removed  are  boiled, 
beginning  with  cold  water,  after  previous  soaking,  the  loss 
is  large.  Omitting  the  soaking  greatly  diminishes  the  loss, 
as  also  does  placing  the  potatoes  immediately  in  hot 
water. 

,  2.    When  potatoes  are  boiled  without  removing   the 
skins,  the  loss  is  small,  almost  negligible. 

3.  The  lo'ss  in  boiling  carrots  is  large,  one-quarter  or 
more  of  the  dry  matter,  but  is  greatest  when  they  are  cut 
in  small  pieces. 

4.  The  loss  in  cooking  cabbage  is  still  larger,  amounting 
to  more  than  one-third  of  the  dry  matter.     The  loss  is 

1  Bui.  43,  O.E.S. 


Effect  of  Cooking  on  Food  Efficiency          319 

not  very  much  diminished  by  using  hot  water  at  the  start. 
It  was  found  that  making  the  water  alkaline  increased  the 
.loss  of  protein  nitrogen. 

304.  Influence  of  cooking  upon  nutritive  efficiency.  — 
The  effect  of  these  complex  changes  upon  the  nutritive 
efficiency  of  foods  it  is  not  easy  to  measure.  There  is  no 
reason  for  supposing  that  the  various  nutrient  compounds 
are,  in  any  case,  so  modified  as  to  change  the  office  they 
perform  in  building  and  maintaining  the  human  body. 
The  only  factor  to  consider,  then,  is  the  influence  of  cook- 
ing upon  digestibility.  Such  observations  as  have  been 
made  with  raw  and  cooked  meats  indicate  that  the  diges- 
tion of  the  latter  may  be  no  less  complete,  but  is  slower. 
Doubtless  the  same  is  true  of  eggs.  On  the  other  hand, 
the  cooking  of  cereals  and  vegetables  can  but  greatly 
increase  the  ease  and  rapidity  of  digestion.  Unless  the 
cells  were  previously  ruptured,  the  digestive  juices  would 
slowly  reach  and  act  upon  the  starch  granules  and  other 
bodies  inclosed  in  the  cellulose  covering.  With  many 
foods  cooking  may  be  said  with  truth  to  be  the  prelimi- 
nary step  to  rapid  and  the  completest  possible  digestion. 


CHAPTER  XVII 
FOOD  SANITATION 

FOOD  sanitation  is  now  a  subject  of  the  highest  impor- 
tance. Either  because  of  their  source  or  condition, 
human  foods  may  be  the  direct  cause  of  disease,  some- 
times because  they  communicate  to  the  human  subject 
pathogenic  germ  life,  and  sometimes  because  of  the 
physiological  effect  of  compounds  that  they  contain 
naturally,  or  that  have  developed  in  them  by  holding 
them  under  undesirable  conditions.  With  the  changes 
in  commercial  conditions  caused  by  the  increasing  spread 
and  density  of  our  population,  the  defense  of  the  public 
against  dangerous  food  materials  has  become  an  exceed- 
ingly complex  and  difficult  matter. 

There  are  several  reasons  for  this,  among  which  are  the 
following :  — 

^f^rhe  collection  of  raw  food  materials  over  wide  areas 
from  sources  it  is  not  easy  to  supervise  or  even  know  much 
about. 

2.  The  transportation  of  foods  over  long  distances,  with 
the  attendant  danger  of  fermentative  changes  and  con- 
tamination. 

3.  The  exposure  of   foods  to  dust  and   flies,  especially 
in  city  markets. 

4.  The  storage  of  foods  during  long  periods  of  time  with 
consequent  changes  in  their  composition. 

320 


Food  Sanitation,  —  CWs  Milk  321 

introduction  into  foods,  especially  meats  and 
canned  goods,  of  compounds  known  as  preservatives, 
that,  when  introduced  into  the  digestive  tract,  may  be 
deleterious  to  health. 

In  order  to  control  these  conditions,  national,  state,  and 
municipal  regulations  have  been  adopted  which  have  done 
much  to  improve  the  quality  and  healthfulness  of  com- 
mercial human  foods.  Such  control  is  more  or  less 
imperfect,  however.  The  best  defense  against  unhealthful 
foods  is  such  an  understanding  on  the  part  of  the  purchaser 
of  the  sources  of  danger  as  to  permit  a  wise  discrimination 
in  the  selection  of  foods  and  in  the  conditions  to  which 
they  are  submitted. 

A.   Cow's  MILK 

There  is  no  food  which  has  been  the  subject  of  more  in- 
vestigation as  to  its  sanitary  relations,  or  concerning  which 
there  has  been  more  regulative  legislation  in  order  to  insure 
healthful  quality,  than  is  the  case  with  cow's  milk.  This  is 
justified  by  the  importance  of  this  milk  as  human  food. 
Not  only  is  it  quite  generally  consumed  by  adults,  but  it 
constitutes  the  entire  food  of  many  infants,  and  forms 
a  generous  share  of  the  diet  of  thousands  of  young  children. 
The  fact  that  this  article  of  food  may  exert  a  determina- 
tive influence  upon  the  health  of  the  young,  and  therefore 
upon  the  physical  status  of  the  adult,  raises  it  to  a  position 
of  supreme  importance.  It  is  essential,  therefore,  that 
those  who  control  the  milk  supply  for  the  family  and  for 
institutions  shall  be  able  to  exercise  an  intelligent  judgment 
concerning  its  quality. 


322  Principles  of  Human  Nutrition 

305.  Ways  in   which   quality   of    milk  is   modified.  — 
There  are  several  ways  in  which  the  sanitary  or  other 
qualities  of  normal  milk  may  be  modified,  of  which  the 
following  are  the  principal:  — 

y:  Adulteration  by  the  addition  of  water,  causing  a 
reduction  of  food  value. 

3.  The  removal  of  a  portion  of  the  milk  solids. 

&r'The  introduction  of  non-pathogenic  germ  life  after 
it  is  drawn  from  the  cow,  causing,  under  certain  conditions, 
undesirable  fermentations. 

^>The  introduction  of  pathogenic  germ  life  after  the 
milk  is  drawn  from  the  cow,  rendering  the  milk  a  means  of 
communicating  infectious  diseases. 

5.  The   introduction   of    disease   germs   through    the 
udder  of  the  cow. 

6.  The  introduction  of  compounds  known  as  preserva- 
tives, having  for  their  purpose  the  prevention  of  fermenta- 
tions in  milk  that  must  be  kept  a  long  time  before  consump- 
tion. 

306.  What   is   normal   milk  ?  —  Before  discussing  the 
various  ways  in  which  milk  may  be  harmed  for  human 
consumption,  it  is  well  to  form  a  clear  idea  of  what  normal 
milk  is.     It  is,  in  brief,  such  milk  as  the  child  draws  from 
the  breast  of  a  perfectly  healthy  mother,  or  the  calf  from 
the  udder  of  the  healthy  cow.     It  is  fresh  milk  from  a 
healthy  mammal,  to  which  nothing  whatever  has  been 
added,  even  of  invisible  germ  life,  from  which  nothing  has 
been  taken,  and  in  which  no  changes  have  occurred.     It  is 
milk  that  would  keep  sound  for  a  long  time,  and  which 
might  be  given  to  infants  with,  the  assurance  that  it  is 
wholesome  and  free  from  any  form  of  infectious  disease. 


Adulteration  of  Milk  323 

It  is  such  milk  as  is  found  in  the  village  or  city  supply  only 
when  it  is  drawn  and  handled  by  expensive  and  elaborate 
methods  that  are  rigidly  controlled.  Only  a  minute  per- 
centage of  commercial  milk  can  be  considered  as  normal 
when  it  reaches  the  consumer.  Even  that  which  is  found 
orr  the  tables  of  farm  homes  is  far  from  normal,  for  it  must 
be  confessed  that  much  milk  used  for  home  consumption 
is  badly  managed. 

307.  The  adulteration  of  milk  with  water.  —  As  will  be 
seen  elsewhere  in  this  volume,  the  normal  milk  of  all 
species  of  animals  contains  a  large  percentage  of  water, 
that  of  the  cow  varying  from  84  to  89  per  cent  as  nearly 
extreme  limits.  It  is  evident,  therefore,  that  cow's  mHk 
has  no  standard  composition;  for  it  varies  with  breed, 
period  of  lactation,  and  from  other  less  definite  causes. 
Because  milk  intended  for  domestic  consumption  has 
been  mostly  sold  by  volume  without  much  opportunity  on 
the  part  of  the  purchaser  to  know  its  composition,  pro- 
ducers and  middlemen  have  not  always  resisted  the  temp- 
tation to  increase  their  profits  by  adding  water.  The 
milkman  and  the  pump  handle  have  long  been  associated 
in  the  -minds  of  consumers  of  "  blue  "  milk.  It  is  pos- 
sible to  add  a  certain  proportion  of  water  to  the  milk  of 
one  breed  of  cows  without  reducing  its  quality  below  that 
of  some  other  breed,  and  even  the  thinnest  normal  milk 
may  be  rendered  more  dilute  without  the  consumer  being 
able  to  detect  the  fraud.  Nothing  short  of  an  examination 
of  the  original  milk  in  comparison  with  the  suspected 
sample  is  competent  to  detect  all  degrees  of  adulteration 
with  water,  though  the  grosser  dilutions  may  be  established 
on  other  grounds. 


324  Principles  of  Human  Nutrition 

308.  Effect  of  adulteration.  —  It  cannot  be  claimed  that 
the  adulteration  of  milk  with  water  renders  it  unsanitary 
or  unhealthful,  except  that  the  food  value  may  be  reduced 
to  a  point  that,  in  particular  instances  where  milk-  is  the 
chief    article   of    diet,    would    cause    undernourishment. 
Much  market  milk  has  not  contained  over  12.5  to  13  per 
cent  solid  matter,   and  when  in  sound  condition  it  is 
considered  a  healthful  article  of  food.     It  is  absurd,  there- 
fore, to  claim  that  the  reduction  of  rich  Jersey  or  Guern- 
sey milk  to  as  low  a  standard  by  the  addition  of  pure  water 
renders  it  unhealthful.     The  claim  that  the  consumer  may 
rightfully  make  is  that  he  is  defrauded  when  he  pays  for 
normal  milk  and  gets  a  diluted  article. 

309.  Milk  standards.  —  In  recent  years  the  national 
government  and  some  state  governments  have  established 
food  standards,  including  milk,  have  provided  penalties 
for  the  sale  of  foods  falling  below  the  standards  and  the 
necessary  machinery  for  enforcing  such  regulations.     In 
the  state  of  New  York,  the  legal  standard  for  cow's  milk, 
below  which  it  must  not  fall,  is-HJi_per  cent  total  solids, 
and  3  per  cent  of  fat.     It  is  provided,  however,  that  if  it 
can  be  shown  that  the  normal  milk  of  the  cow  or  herd  from 
which  the  milk  is  produced  is  below  that  standard,  no 
penalty  is  attached  to  its  sale.     This  law  has  accomplished 
much  good ;  but,  on  the  other  hand,  it  is  quite  evident  that 
this  legislation  has  tended  to  reduce  a  large  proportion  of 
market  milk  to  approximately  the  legal  standard  through 
the  keeping  of  cows  giving  a  large  volume  of  thin  milk.     A 
much  more  sensible  plan  would  be  to  permit  the  vender  of 
milk  to  guarantee  a  standard  for  his  goods  and  then  hold 
him  responsible  for  meeting  it. 


Bacteria  in  Milk  325 

310.  The  removal  of  a  portion  of  the  milk  solids.  — 
(This  is  done  by  the  removal  of  cream\    The  effect  of  this 

is  to  decrease  the  proportion  of  solids  in  the  milk,  and  to 
decrease  the  proportion  of  fat  in  the  solids  that  remain  be- 
hind. Because  cream  bears  a  much  higher  price  than  whole 
milk,  some  dealers  have  practiced  removing  the  cream 
from  the  top  of  the  cans,  the  partially  skimmed  milk 
being  sold  at  the  price  of  whole  milk.  The  practice  of  par- 
tially creaming  table  milk  has  evidently  been  followed  by 
hotels  and  restaurants,  if  we  may  judge  by  the  quality  of 
the  milk  that  is  furnished  to  guests  to  drink.  In  such  cases, 
the  laws  intended  to  maintain  commercial  milk  up  to  a 
certain  standard  fail  to  defend  the  actual  consumer  against 
an  inferior  article,  and  really  operate  to  increase  the  gains 
of  the  dishonest  purveyor.  Just  why  the  hotel  keeper 
should  be  protected  against  fraud  and  then  be  permitted 
to  offer  illegal  milk  to  his  guest  is  not  clear.  It  would 
seem  that  the  law  should  protect  the  individual  who 
actually  uses  the  milk  as  food. 

311.  The  introduction  into   cow's   milk  of  non-patho- 
genic germ  life.  —  Normal  cow's  milk  as  it  comes  from  the 
udder  is  not  entirely  free  from  germ  life,  but  the  number  of 
germs  present  are  few.     With  the  procedure  ordinarily 
followed,  milk  almost  immediately  acquires  bacteria,  and 
under  some   circumstances   continues   to   do  so.     These 
organisms  have  their  source  in  the  dust  in  the  stable  air, 
dirty  utensils,  the  surface  of  the  cow,  the  hands  and 
clothes  of  the  milker,  and  exposure  to  dirt  and  air  in  the 
house  or  during  transportation.     The  germ  life  included 
in  this  class,  that  is,  the  non-pathogenic,  cannot  of  itself 
produce  disease.     Apart  from  its  effect  on  the  milk,  it  is 


326  Principles  of  Human  Nutrition 

entirely  harmless  to  the  human  subject.  It  is  very  unde- 
sirable to  have  milk  heavily  loaded  with  bacteria,  however, 
especially  that  which  must  be  held  for  some  time  before 
consumption,  or  is  to  be  kept  under  conditions  favorable  for 
the  growth  of  germ  life,  for  the  fermentations  which  these/ 
organisms  cause  render  the  milk  unsound.  Such  milk  is 
inferior  in  taste,  and  is  unfit  for  feeding  infants,  as  with  the 
latter  it  induces  diarrhea  and  cholera  infantum,  especially 
during  the  heated  season. 

312.  The  introduction  of  pathogenic  (disease)  germs 
after  the  milk  is  drawn.  —  It  is  well  established  that 
epidemics  ofjtyphoid  fever  have  been  caused  by  the  distri- 
bution of  the  germs  of  this  disease  in  milk.  There  appears 
to  be  good  evidence  that  cases  of  scarlet  fever  and  diph- 
theria have  originated  in  the  same  way.  These  particular 
germs  are  communicated  to  the  milk  after  it  leaves  the 
cow's  udder,  for  the  bovine  species  is  not  subject  to  the 
diseases  mentioned.  The  source  of  such  disease  germs  in 
milk  is  directly  or  indirectly  some  diseased  person,  perhaps 
convalescent,  who  comes  in  contact  with  the  milk  or  milk 
utensils,  or  who  inhabits  the  premises  where  the  milk  is 
produced.  Fresh  infectious  material  having  its  source 
in  feces,  the  skin,  or  sputum,  may  find  its  way  into  milk, 
especially  where  cleanly  habits  are  not  maintained  on  the 
part  of  the  infecting  individual.  The  danger  is  augmented 
in  the  case  of  typhoid  fever  by  the  fact  that  the  disease 
may  exist  for  some  time  before  being  recognized,  and  the 
so-called  "  walking  "  cases  are  even  more  to  be  feared, 
where  the  disease  germs  may  inhabit  an  individual  for  long 
periods  of  time  without  discovery.  Such  cases,  when 
located  on  a  farm,  are  a  distinct  menace  to  the  sanitary 


Infection  of  Milk  327 

quality  of  milk  and  other  foods.  Outside  of  the  diseases 
mentioned,  it  is  possible  for  milk  to  be  infected  with  the 
germs  of  tuberculosis  when  this  disease  exists  in  the  family 
where  the  milk  is  produced  or  handled.  This  is  a  danger 
scarcely  appreciated  by  the  great  majority  of  persons. 

313.  Infection  of  milk  from  diseased  cows.  —  Tuber- 
culosis, which  is  practically  the  only  bovine  disease  that 
it  is  necessary  to  consider  in  this  connection,  is  very  preva- 
lent among  dairy  cows.     It  is  possible  that  one-tenth  of 
the  cows  in  New  York  are  affected  with  this  ailment,  and 
perhaps  more.     Under  certain  conditions,  the  bacteria  of 
tuberculosis  are  conveyed  to  milk  through  the  udder. 
Milk   so   contaminated  is   a  menace  to  human  health. 
Fortunately  only  a  small  per  cent  of  the  diseased  cows  are 
dangerous  in  this  way.     Much  investigation  and  discus- 
sion has  been  given  to  the  relation  between  human  and 
bovine  tuberculosis,  and  it  now  seems  more  than  probable 
that  the  danger  to  the  human  family  from  the  bovine  germ 
has  been  overestimated.     The  best  authorities  have  come 
to  hold  that  tuberculosis  of  the  lungs  will  not  be  contracted 
from  infected  milk,  or  rarely,  and  that  the  chief  danger  is 
that  such  milk  may  be  a  source  of  glandular  tuberculosis 
with  children.     In  any  case,  tuberculous  persons  not  under 
control  are  a  vastly  greater  menace  to  humankind  than 
are  tuberculous  cows. 

314.  The  precautions  necessary  to  secure  pure  milk.  - 
Housewives,   and  especially  persons  responsible  for  the 
supply  of  milk  to  hospitals  and  other  institutions,  should 
understand  the  conditions  necessary  to  the  production  and 
handling  of  milk  in  order  to  secure  a  pure  and  safe  prod- 
uct.    They  are  as  follows:  — 


328  Principles  of  Human  Nutrition 

Jx"Clean  premises  where  milk  is  produced,  including 
the  stable  and  its  surroundings.  An  accumulation  of 
filth  in  immediate  contact  with  the  stable  should  be 
avoided.  If  possible,  the  excreta  from  the  cows  should 
be  at  once  removed  to  some  distance  from  the  stable. 

2>-Cows  should  not  be  milked  while  the  air  is  heavily 
la'den  with  dust  from  the  moving  of  hay  and  litter.  It  is 
possible  to  so  arrange  the  feeding  and  milking  periods  as 
to  avoid  this. 

3^>The  cows  should  be  kept  as  free  as  possible  from  dirt 
and  dust  by  thorough  brushing.  The  long  hair  around  the 
udder  should  be  clipped  short,  and  especially  before  milk- 
ing should  the  udder  be  thoroughly  brushed  and  then 
rubbed  with  a  moist  cloth. 

hands  and  clothing  of  the  milker  should  be  clean, 
milking  utensils  should  be  cleaned  and  sterilized 
by  heat  in  the  most  thorough  manner. 

6^,  Special  forms  of  milking  pails  should  be  used  that 
protect  the  milk  as  fully  as  possible  while  it  is  being  drawn. 

/^Persons  afflicted  with,  or  convalescent  from,  infec- 
tious diseases  should  be  kept  away  from  the  stables,  milk, 
and  milk  utensils.  It  is  almost  criminal  for  such  persons 
to  be  allowed  to  infect  milk  and  thereby  cause  epidemics 
of  diseases  dangerous  to  human  life. 

S^The  herd  should  be  inspected  at  intervals  for  the 
presence  of  tuberculosis,  and  if  diseased  cows  are  found, 
they  should  be  isolated  from  the  well  animals,  and  their 
milk  should  neither  be  sold  nor  used  in  the  home  unless 
previously  pasteurized.  With  the  knowledge  now  pos- 
sessed, no  milk  producer  has  any  right,  even  unknowingly, 
to  distribute  milk  from  tuberculous  animals.  It  is  time 


Water  and  Disease  329 

for  a  general  demand  from  consumers  that  herds  produc- 
ing their  milk  supply  shall  be  tested  for  affected  animals. 
315.  Pasteurization  of  milk  as  a  safeguard  against 
the  effects  of  pollution.  —  It  has  often  been  advocated 
that  the  consumers  of  milk  in  cities  be  safeguarded 
against  the  effects  of  polluted  milk  by  requiring  that  the 
entire  city  supply  be  pasteurized.  Legislation  to  this 
effect  has  been  proposed,  but  it  has  been  opposed  by  the 
rational  argument  that  such  a  provision  places  clean  and 
unclean  milk  on  the.  same  commercial  level,  and  would 
greatly  reduce  the  incentive  for  the  production  of  milk  of 
good  sanitary  quality.  Pasteurization  would  simply 
"  throw  a  blanket  "  over  dirty  and  infected  milk,  and 
would  check  the  campaign  of  education  for  a  better  milk 
supply.  It  is  probable,  too,  that  milk  heated  to  155°F.,  or 
higher,  is  not  as  well  adapted  to  the  stomachs  of  infants  and 
invalids,  as  is  clean  raw  milk.  The  requirement  should 
rest  on  the  producer  to  market  a  healthful  article,  and  he 
should  be  given  no  excuse  for  doing  otherwise. 

B.  WATER  AS  A  SOURCE  OF  DISEASE 

/  No  article  of  food  is  used  more  constantly  or  in  larger 
(quantities  than  is  water.  At  the  same  time,  no  food 
material  is  more  dangerous  as  a  carrier  of  disease.  This 
is  shown  by  the  serious  epidemics  of  typhoid  fever  and 
other  maladies  which  infected  water  has  caused.  The 
dangers  in  this  direction,  at  least  for  the  inhabitants  of 
large  villages  and  cities,  are  augmented  by  the  fact  that 
their  water  supply  comes  in  most  instances  from  extensive 
watersheds,  or  from  rivers  or  lakes,  subject  to  pollution, 
and  in  any  case,  from  sources  not  under  the  immediate 


330  Principles  of  Human  Nutrition 

control  of  the  user  and  about  the  condition  of  which  he 
generally  has  very  little  or  no  accurate  knowledge. 

316.  Pure  water.  —  Pure  water,  chemically  speaking, 
consists  entirely  of  the  compound  HgO,  without  the  presence 
of  any  other  compound  or  foreign  bodies.     In  this  sense, 
there  are  no  natural  waters  that  are  pure.     Even  the  first 
rain  water  that  falls  brings  down  with  it  dust  and  gases 
from  the   air.     The   only  waters   that   approximate   {<Tj 
chemical   purity  are   carefully  distilled  water   and  rain 
water,  after  the  rain  has  been  falling  for  a  few  hours? 
The  term  "  pure,"  as  popularly  applied  to  water,  as  for  in- 
stance to  the  water  of  springs,  signifies  that  the  water  is 
free  from  undesirable  compounds  or  bodies,  that  is,  that  it 
is  of  good  sanitary  quality.     Natural  waters  from  unin- 
habited regions  and  from  carefully  guarded  sources  in 
inhabited    places    are  of    this    kind.     Springs,    streams, 
and  lakes  along  which  or  near  which  there  are  no  inhabit- 
ants, and  the  vicinity  of  which  is  not  frequented  by  any 
number  of  people,  or  streams  and  storage  reservoirs  that 
are  carefully   policed,  furnish  the    safest    water    supply, 
excepting,  possibly,  deeply  driven  wells  where  the  water 
entering  them  is  subject  to  effective  ground  filtration. 

317.  The   impurities   of   water.  —  The  various  sources 
to  water  of  compounds  of  bodies  foreign  to  itself,  some 
dangerous  and  some  not,  are  as  follows  :  — 

1.  Substances  washed  out  of  the  air  by  falling  rain. 
These  consist  mainly  of  nitrogen  compounds,  nitrates  and 
nitrites  of  ammonia,  carbon  dioxid,  and  particles  of  dust. 
The  latter  contains  germ  life  which  is  dangerous  only  in 
exceptional  cases.  Rain  water,  at  least  after  ground  fil- 
tration, and  certainly  that  which  falls  after  the  first 


Water  and  Disease  331 

hour  or  so,  must  be  regarded  as  of  excellent  sanitary 
quality. 

2.  Water  takes  into  solution  substances  from  the  soil. 
When  the  soil  has  not  been  polluted  with  animal  matter, 
these  impurities   do  not   convey  disease.     They   consist 
mostly  of  inorganic  salts,   carbonates,  nitrates,  sul fates, 
and  chlorides,   chiefly  of  the  bases  potassium,   sodium, 
calcium,  magnesium,  and  iron.     Occasionally  some  of  the 
less  common  metals  are  found,  such  as  lithium.     Ordi- 
narily, these  salts  are  not  present  in  such  quantities  in 
natural  water  as  to  render  them  unfit  for  domestic  use, 
although  some  springs  are  so  charged  with  certain  com- 
pounds, of  which  magnesium  sulfate  is  an  example,  that 
their  water  has  a  pronounced  medicinal  effect. 

Organic  matter  exists  only  in  those  natural  waters  that 
ooze  out  of  or  filter  through,  deposits  of  vegetable  mat- 
ter such  as  leaf  mold  and  peat.  While  such  material  in 
solution  may  give  water  a  dark  color  and  make  it  look 
very  impure,  there  is  no  evidence  that  the  health  of  the 
user  would  thereby  be  affected. 

3.  The  waters  that  menace  human  health  are  generally 
those  that. .are  contaminated  by  human  excreta.     Both 
private  and  public  water  supplies  may  become  unfit  for 
use,  in  this  way.      Numerous   instances   are   on   record 
where  wells  have  become  infected  from  nearby  cases  of 
typhoid  fever,  thereby  causing  a  spread  of  this  disease, 
or    where    public    water    systems    polluted    with    infec- 
tious material  have  caused  serious  epidemics  of  various 
maladies. 

318.  Certain  precautions  are  necessary  to  insure 
sanitary  water  for  domestic  use.  —  (1)  No  water  should 


332  Principles  of  Human  Nutrition 

be  used  from  a  well  which  can,  by  any  possibility,  be  con- 
taminated from  a  nearby  cesspool,  or  that  is  so  built  as  to 
allow  the  direct  entrance  .of  surface  wash.  Farm  wells 
remote  from  cesspools,  with  proper  covers,  and  into  which 
water  can  ^flow  only  after  it  filters  through  several  feet  of 
soil,  are  a  fairly  safe  source  of  water,  provided  the  excreta 
of  diseased  persons  on  the  farm  are  properly  disposed  of. 
Even  if  a  well  is  distant  from  a  cesspool,  care  should  be 
taken  that  the  soil  strata  do  not  incline  from  the  cesspool 
toward  the  well,  especially  where  a  sandy  or  gravelly  sur- 
face stratum  is  underlaid  by  a  stratum  of  dense  clay.  In 
villages  and  cities,  wells  should  always  be  regarded  with 
suspicion,  because  they  are  liable  to  contamination  in  ways 
that  are  not  easily  prevented. 

(2)  Public  water  supplies  are  safe  only  when  the  water  is 
conveyed  in  pipes  from  an  indisputably  pure  source,  or 
where,  if  contamination  is  possible,  the  best  modern 
devices  are  adopted  to  render  the  water  sanitary.  Water 
from  a  lake  or  stream  into  which  sewage  enters,  or  the 
borders  of  which  are  thickly  populated,  should  always  be 
regarded  as  dangerous  to  health,  and  the  citizens  of  any 
village  or  city  should  protest  against  such  a  supply  unless 
it  is  rendered  sanitary  by  certain  modern  devices.  The 
defense  of  the  family  against  suspected  water  is  thorough 
boiling,  to  kill  any  disease  germs  which  it  may  contain. 

C.    RELATION  OF  ICE  TO  HEALTH 

Ice  is  now  very  generally  used  for  domestic  purposes, 
especially  in  cities.  As  a  means  of  maintaining  low  tem- 
peratures for  the  preservation  of  food  materials  it  is  ex- 
tremely useful.  Used  in  this  way,  it  cannot  possibly  be  a 


Dangers  from  Ice  333 

menace  to  health.  If  it  is  dangerous  at  all,  it  is  only 
through  the  enormous  quantities  introduced  into  foods 
and  drinks  that  it  can  by  any  possibility  be  a  vehicle  of 
disease. 

319.  Does  ice  ever  carry  disease  germs  ?  —  A  general 
opinion  prevails  that  water  purifies  itself  from  foreign 
matter  on  freezing.  This  does  not  appear  to  be  strictly 
true.  Both  natural  and  artificial  ice  are  not  always  free 
from  living  bacteria  or  other  micro-organisms.  This  i& 
made  clear  by  various  observers.  Epidemics  of  diseasd 
have  been  attributed  to  contaminated  ice,  or  frozen  snow] 
upon  evidence  that  appears  to  be  fairly  reliable.  Ice 
that  comes  from  rivers  or  ponds  which  are  a  receptacle  for 
sewage  or  human  dejecta  is  to  be  regarded  with  suspicion. 
On  the  other  hand,  the  freezing  of  water  tends  to  purify  it 
through  exclusion  of  foreign  matter.  More  than  this, 
only  a  small  proportion  of  individual  bacteria  survive  a 
freezing  temperature,  especially  when  this  temperature 
lasts  for  a  considerable  period  of  time ;  and  those  that  sur- 
vive are  regarded  as  being  less  virulent. 

However,  ice  pollution  may  have  other  sources  than 
the  pond  or  river,  among  which  may  be  named  filthy 
workmen,  the  droppings  of  horses  used  on  the  ice  field, 
and  the  dirty  materials  in  which  the  ice  is  packed.  Of 
course  the  washing  of  ice  by  pure  water,  or  by  its  own 
melting,  cleanses  it  from  superficially  attached  matter. 
When  everything  is  considered,  however,  public  ice  supplies 
cannot  be  regarded  as  safely  sanitary,  even  in  the  case  of 
artificial  ice,  which  may  be  subjected  to  some  of  the  same 
sources  of  infection  as  natural  ice,  and,  because  it  is 
promptly  used,  may  be  more  dangerous.  The  only  ice 


334  Principles  of  Human  Nutrition 

/that  is  sure  to  be  sanitary  is  that  which  is  made  from  pure 
j  water  and  is  handled  in  a  cleanly  manner.  Housewives 
should  be  advised  that  there  is  more  or  less  danger  in  the 
promiscuous  use  of  ice  in  drinks  unless  its  source  guar- 
antees its  purity.  When  used  for  cooling  water,  danger 
can  be  averted  by  setting  a  receptacle  containing  the  ice 
into  the  water  to  be  cooled,  rather  than  putting  the  ice 
directly  into  the  water.  Such  a  precaution  is  worth  while, 
even  though  the  chances  of  the  conveyance  of  disease  by 
ice  are  rather  small. 

D.     UNHEALTHY  MEATS  AND  VEGETABLES 

While  water  and  milk  are  doubtless  the  most  important 
food  materials  in  their  relation  to  disease,  other  foods 
should  be  considered  in  this  connection.  These  include] 
meats,  raw  oysters,  milk  products,  fruits,  vegetables,  and 
certain  commercially  prepared  foods,  indeed,  any  material 
which  is  subject  to  injurious  fermentation  or  to  contamina- 
tion in  preparation  and  through  handling  in  the  marketv 
It  may  be  said  in  a  general  way  that  the  causes  of  unhealth- 
fulness  in  these  foods  may  arise  from  two  general  causes, 
viz.  (1)  the  acquisition  of  disease-producing  forms  of 
life  from  without,  and  (2)  the  development  within  of 
disease  organisms  or  of  toxic  bodies  through  fermentative 
processes.  Certain  of  these  disease-producing  conditions 
rarely  occur.  The  danger  from  them  is  slight  as  expe- 
rience shows,  and  all  such  dangers  may  usually  be  avoided 
by  intelligent  precautions. 

The  disease  organisms  that  may  be  found  in  the  tissues 
of  animals  used  for  food  are  trichina  and  the  germs  of 
tuberculosis. 


Trichinosis  —  Tuberculosis  335 

320.  Trichinosis.  —  Since  1860  it  has  been  known  thai/ 
the  muscular  tissue  of  swine  is  sometimes  infested,  though 
perhaps  rarely  now,  with  a  minute  parasitic  worm  knowiji 
as  the  Trichina  spiralis.     It  is  parasitic  on  other  domestic 
animals,  particularly  cats,  rabbits,  rats,  and  mice.     The 
young  worms,  after  developing  from  the  eggs,  become 
imbedded  by  millions  in  the  muscles  of  the  hog,  and  are 
then  invisible  to  the  naked  eye.     After  a  time,  they  be- 
come encysted,  and  at  the  end  of  a  year  or  so  are  visible  to 
the  naked  eye  as  specks  scattered  through  the  muscular 
tissue  or  red  meat.     In  this  form,  the  worms  are  dormant, 
and  may  live  a  long  time.     When  uncooked  pork  so  in- 
fested is  eaten  by  man,  the  worms  are  liberated,  attach 
themselves  to  the  lining  of  the  stomach,  and  the  females 
produce  broods,  sometimes  of  as  many  as  a  thousand  young 
worms.    ^These  young  find  their  way  into  the  tissues  oT\ 
the  intestines,  and  finally  throughout  the  whole  systemy 
It  seems  that  with  the  rarity  of  this  disease  in  swine,  and 
with  present  methods  of  inspection,  pork  infested  in  this 
way  very  seldom  finds  its  way  into  the  family  larder.     In 
any  case,  the  thorough  cooking  of  pork  renders  it  a  safe 
food. 

321.  Tuberculosis.  —  The  widespread  existence  of  this 
disease  not  only  among  dairy  cows,  but  among  animals 
slaughtered  for  meat,  even  those  raised  and  fed  on  the 
western  plains,  has  rendered  the  public  solicitous  concern- 
ing the  healthfulness  of  beef,  so  much  of  which  is  eaten 
without   thorough   cooking.     There   is   a  not   unnatural 
prejudice  against  eating  the  flesh  of  an  animal  known  to 
have  been  affected  with  tuberculosis ;  and  in  dealing  with 
this  disease  in  the  way  of  suppression,  animals  so  affected 


336  Principles  of  Human  Nutrition 

have  quite  generally  been  killed  and  buried.  The  indis- 
criminate rejection  of  such  animals  for  human  consump- 
tion has  undoubtedly  caused  the  waste  of  a  large  amount 
of  perfectly  safe  food  material.  Experience  has  shown  that 
the  flesh  of  animals  that  are  affected  with  tuberculosis 
within  certain  limits  may  be  safely  used  as  food  for  man. 
This  is  so  because  of  the  nature  of  the  disease.  Its  effect, 
at  first  at  least,  is  not  to  diffuse  diseased,  toxic  or  infec- 
tious material  throughout  the  entire  mass  of  the  animal's 
body,  but  to  destroy  the  tissue  of  certain  glands  or  organs 
in  which  it  gains  a  foothold.  The  regulations  of  the 
federal  meat  inspection  that  have  been  established  in  the 
large  abattoirs  permit  the  carcasses  of  animals  to  be  sold 
as  sound  when  the  lesions  (diseased  tissues)  are  localized 
and  are  restricted  to  certain  organs,  and  exist  in  the  less 
dangerous  forms.  It  is  not  true,  then,  that  the  flesh  of  all 
tuberculous  animals  is  unfit  for  human  food,  or  that  such 
meat  is  wholly  excluded  from  the  market,  even  under  the 
most  rigid  inspection.  There  is  good  reason  for  maintain- 
ing inspection,  and  consumers  have  a  right  to  demand  that 
this  be  of  the  most  thorough  kind. 

322.  Raw  oysters  as  a  source  of  disease.  —  There  is  no 
doubt  but  that  at  least  one  epidemic  of  typhoid  has  been 
caused  by  infectious  material  contained  in  uncooked 
oysters.  Reference  is  made  to  twenty-five  cases  of 
typhoid  fever  among  the  students  of  Wesley  an  University, 
Middletown,  Conn.,  in  the  fall  of  1894.  It  was  shown  that 
these  oysters  were  "  fattened  "  near  the  mouths  of  sewers, 
one  of  which  led  from  a  private  house  where  two  cases 
of  typhoid  had  occurred.  It  is  necessary  to  conclude 
that  when  oysters  are  placed  near  the  mouths  of  sewers 


Infected  Foods  337 

they  are  a  menace  to  human  health  when  eaten  raw. 
But  there  is  danger  of  unduly  magnifying  this  danger,  for 
most  oysters  are  not  subject  to  such  contamination,  and 
the  widespread  use  of  raw  oysters  does  not  seem  to  be  at- 
tended with  bad  results.  At  the  same  time,  it  is  possible 
that  the  sporadic  cases  of  typhoid  fever,  which  so  fre- 
quently occur,  may  be  explained  through  the  conveyance 
of  infectious  material  in  oysters.  It  is  rational  to  de- 
mand, therefore,  that  no  oysters  shall  be  grown  near  the 
mouths  of  sewers. 

323.  Conveyance  of  infectious  diseases  by  fruits  and 
vegetables.  —  The  chances  of  the  contamination  of  fruit 
and   vegetables   with   infectious   material   are   not   very 
remote.     In  the  first  place  market  gardeners  who  use  al 
city  supply  of  animal  manure  in  contact  with  small  fruits) 
and  vegetables  are  not  unlikely  to  market  a  contaminated  I 
product.     Moreover,  the  vegetables  and  fruits  displayed^ 
on  the  streets  and  even  in  shops,  in  a  majority  of  instances, 
are^swarmirig._,with  flies.     When  it  is  realized  that  these 
flies  may  have  walked  over  cesspool  deposits  and  are  thus 
conveying  infectious  germs  on  their  feet,  as  flies  are  known 
to  do,  confidence  in  such  exposed  food  materials  is  shaken. 
These  facts  should  lead  the  housewife  to  patronize  gro- 
ceries where  the  commodities  are  kept  shielded  from  flies, 
and  to  give  all  fruits  and  vegetables  a  thorough  cleansing 
before  they  are  eaten,  especially  if  they  are  to  be  eaten  in 
the  uncooked  state. 

324.  Cooking  as  a  safeguard  against  disease.  —  From 
the  foregoing  statements  it  is  easy  to  see  that  there  are 
good  reasons  outside  the  matter  of  palatableness  for  thor- 
oughly cooking  meats  and  vegetables.      The  eating  in  a 


338  Principles  of  Human  Nutrition 

raw  state  of  vegetables  and  fruits  raised  in  the  home 
garden,  and  such  fruits  as  oranges  and  bananas  from 
which  the  skin  is  removed,  is  generally  not  attended  with 
danger. 

325.  Toxic  effect  of  fermented  meats  and  'milk  prod- 
ucts. —  Numerous  instances  are  on  record  where  serious 
and  sometimes  dangerous  or  even  fatal  illnesses  have 
resulted  from  eating  poultry,  cheese,  and  ice  cream^ 
These  are  explained  by  the  general  statement  that  toxic 
compounds  have  developed  in  these  materials  through 
some  form  of  fermentation,  compounds  that  produce  a 
severe  reaction  on  the  digestive  tract  and  result  in  vomit- 
ing and  diarrhea.  Neither  these  fermentations  nor  their 
products  are  well  understood.  The  practical  fact  for  the 
producer  and  consumer  to  consider  is  that  fresh  products 
and  those  that  have  been  produced  and  held  under  proper 
conditions  of  cleanliness  and  temperature  do  not  become 
dangerous  to  human  health.  The  question  has  been  raised 
whether  poultry  and  other  materials  that  have  been  held 
in  cold  storage  for  a  long  time  are  a  menace  to  health. 
Certainly  immense  quantities  of  foods  so  treated  have  been 
eaten  during  the  past  ten  years,  and  very  little  evidence  of 
dangerous  quality  has  been  obtained.  It  is  conceivable 
that  when  the  conditions  of  storage,  such  as  temperature 
regulation,  are  bad,  an  unhealthy  and  even  dangerous 
product  might  result. 

E.    EFFECT  OF  FOOD  PRESERVATIVES  UPON  HEALTH 

A  practice  has  developed  on  the  part  of  manufacturers 
and  handlers  of  such  food  materials  as  meats,  fish,  canned 
goods,  and  sauces,  of  applying  to  these,  or  introducing 


Use  of  Preservatives  339 

into  them,  certain  compounds  known  as  preservatives. 
The  most  common  of  these  compounds  are  boric  acid, 
salicylic  acid,  and  sodium  salicylate,  benzoic  acid,  sodium 
benzoate,  and  sulfurous  acid  and  sulfites.  Formalde- 
hyde has  also  been  used.  The  effect  of  these  is  to  prevent 
the  activity  of  the  germ  life  that  causes  destructive  changes 
in  animal  and  vegetable  products.  Manufacturers  of 
canned  goods  have  sometimes  found  it  difficult  to  "  pro- 
cess "  their  goods  so  as  to  entirely  prevent  later  fermenta- 
tions and,  at  the  same  time,  not  develop  undesirable  flavors 
in  the  contents  of  the  cans,  and  some  canners  have  at  times 
taken  advantage  of  preservatives  as  an  easy  way  of  over- 
coming this  difficulty.  On  the  other  hand,  many  manu- 
facturers have  withheld  from  this  practice.  Sauces  such 
as  tomato  catsup  have  been  found  to  contain  benzoic 
acid.  Preservatives  have  also  been  used  in  milk,  and 
boric  acid  has  been  found  on  salt  fish  and  meats^  These 
are  merely  examples  of  the  extensive  use  of  preservatives. 
326.  Should  the  use  of  preservatives  in  food  products 
be  permitted?  —  This  matter  has  received  much  atten- 
tion in  the  way  of  scientific  investigation  and  legislation. 
The  most  extended  recent  study  of  this  question  was 
conducted  by  Dr.  H.  W.  Wiley,  chief  chemist  of  the 
U.  S.  Department  of  Agriculture,  and  his  verdict  is  un- 
favorable to  the  use  in  foods  of  any  of  the  common  pre- 
servatives. He  concludes  from  his  data  that  benzoic  aciu 
as  such  or  as  sodium  benzoate,  administered  in  from  1 
to  2  grams  per  day,  causes  disturbances  of  digestion 
attended  by  headache  and  nausea,  loss  of  weight,  and  other 
results ;  that  when  J  gram  of  boric  acid  is  taken  daily,  no 
marked  effects  are  immediately  produced,  but  that  ulti- 


340  Principles  of  Human  Nutrition 

mately  there  is  a  loss  of  appetite,  and  the  general  health 
Buffers,  and  that  a  daily  dose  of  as  high  as  4  to  5  grams 
Ipaused  some  subjects  to  become  ill  and  unfit  for  duty ; 
that  formaldehyde  in  food  "  tends  to  derange  metabolism, 
disturb  the  normal  functions,  and  produce  irritations, 
and  undue  stimulation  of  the  secretory  activities  " ;  that 
salicylic  acid  in  daily  doses  of  .2  gram  to  2  grams,  while 
stimulating  at  first,  ultimately  loses  its  stimulating  prop- 
erty and  "  becomes  a  depressant,"  "tending  to  break 
down  tissues  of  the  body  more  rapidly  than  they  are  built 
up,"  "  disturbs  the  metabolic  processes,"  has  a  tendency 
to  diminish  the  weight  of  the  body,  and  produces  "  a  feel- 
ing of  discomfort  and  malaise"}  that  sulfurous  acid  or 
sodium  sulfite  in  daily  quantities  of  .113  to  .762  gram  of 
the  latter  disturbs  metabolism,  retards  the  assimilation 
of  organic  phosphorous  compounds,  creates  a  "  marked 
tendency  to  the  production  of  albuminuria,"  and  causes 
the  "  impoverishment  of  the  blood  with  respect  to  the 
number  of  red  and  white  corpuscles." 

Protests  against  Dr.  Wiley's  conclusions  caused  the  ap- 
pointment of  a  commission  consisting  of  three  well-known 
biological  chemists,  to  investigate  the  issues  involved. 
This  has  been  done  in  the  case  of  sodium  benzoate,  and 
these  scientists  are  unanimous  in  concluding  that  neither 
small  (.3  gram)  nor  large  (.6  gram  to  6  grams)  daily  doses, 
continued  for  considerable  periods  of  time,  produced  any 
appreciable  effect  upon  the  metabolism  and  health  of  the 
subjects  under  experiment.  If  this  latter  conclusion  is" 
fully  accepted,  then  there  is  no  just  ground  for  excluding 
sodium  benzoate  from  human  foods,  provided  the  existing 
provisions  of  federal  and  state  laws  are  obeyed,  which 


Use  of  Preservatives  341 

Require  that  each  package  of  goods  containing  a  preserva- 
tive shall  carry  a  statement  of  its  kind  and  amount  so 
present.  The  methods  used  by  the  Department  of  Agri- 
culture are  criticised  as  to  the  manner  of  administering 
the  experimental  substances  on  the  ground  that  in  con- 
centrated forms  (in  capsules)  these  substances  are  an  irri- 
tant, but  that  when  taken  in  very  dilute  forms,  evil  effects 
are  not  observed. 

327.  Use  of  food  preservatives  a  doubtful  policy.  — 
After  the  investigation  and  discussion  of  the  past,  there  is 
not  a  general  agreement  that  the  policy  of  permitting  the 
introduction  of  preservatives  into  human  food  is  a  wise 
one,  even  if  food  packages  accurately  state  their  contents. 
First  of  all,  it  is  doubtful  if  the  investigations  so  far  carried 
on  demonstrate  conclusively  that  the  long-continued 
introduction  of  the  preservative  compounds  into  the 
human  system  under  all  conditions  of  age  and  physical 
vigor  is  devoid  of  undesirable  effects.  It  may  be  difficult 
to  secure  convincing  testimony  either  way  on  this  point. 
But  the  absence  of  appreciable  effect  with  vigorous  adults 
during  comparatively  brief  periods  is  not  convincing  evi- 
dence to  those  who  understand  how  subtle  and  difficult  of 
detection  are  the  nutritive  factors  that  determine  our 
bodily  and  mental  states. 

f  The  various  compounds  classed  as  preservatives  have 
/a  strongly  repressive  influence  on  the  unicellular  organisms 
\or  bacteria  that  are  the  direct  cause  of  fermentations. 
These  cells  are  essentially  the  same  in  structure  and  con- 
tents as  those  that  compose  the  tissues  of  the  more  complex 
organisms,  and  it  if  unsafe  to  assume  an  absence  of  effect 
on  any  cellular  tissue.     The  profound  influence  of  the 


342  Principles  of  Human  Nutrition 

chemical  environment  of  living  cells  upon  their  activities 
is  coming  to  be  more  and  more  appreciated  as  we  gain 
added  insight  into  biological  processes.  The  human 
organism,  through  centuries  of  development,  has  been 
brought  into  nutritive  adjustment  and  harmony  with  the 
compounds  present  in  plant  and  animal  tissues,  and  it  is 
unsafe  to  conclude  that  no  deleterious  influence  will  be 
exerted  by  the  life-long  use,  even  in  minute  proportions,  of 
substances  that  exert  so  marked  an  effect  on  the  simpler 
forms  of  life. 

328.  Use  of  food  preservatives  promotes  careless 
methods.  —  It  is  also  urged  that  the  introduction  of  pre- 
servatives into  food  materials  in  order  to  prevent  fermen- 
tations will  permit  careless  methods  of  manufacture  and 
the  use  of  unsound  materials.  There  is  abundant  evidence 
that  all  classes  of  vegetables  and  fruits  may  be  held  in  a 
sound  condition  without  the  use  of  preservatives,  and 
the  presence  of  one  of  these  in  any  food  justifies  the 
suspicion  that  the  manufacturer  is  using  materials  or 
methods  inferior  to  those  of  manufacturers  who  do  not 
add  preservatives  to  their  goods.  It  is  a  very  serious 
question  whether  indicating  the  presence  of  a  preservative 
on  a  food  package  is  an  efficient  defense  of  public  welfare, 
because  a  very  large  proportion  of  consumers  are  neither 
enlightened  nor  warned  by  such  printed  statements. 
Buyers  of  food  supplies  will  do  well  to  give  themselves 
the  benefit  of  the  doubt  as  to  the  healthfulness  of  preser- 
vatives and  purchase  goods  not  containing  them. 


CHAPTER  XVIII 
THE  PRESERVATION  OF  FOOD 

THE  preservation  of  food  materials  may  be  considered, 
from  two  points  of  view:  (1)  the  holding  in  good  condi-l 
tion  for  a  sufficient  length  of  time  the  current  supply  of/ 
food,  and  (2)  the  preservation  for  an  indefinite  period  off 
such  food  products  as  canned  goods  and  preserves. 

Food  preservation  as  a  whole  involves  many  methods 
and  devices.  It  is  not  intended  to  discuss  these  in  detail, 
but  rather  to  set  forth  the  principles  that  are  generally  ap- 
plicable to  the  maintenance  of  food  materials  in  a  sound 
condition. 

329.  Factors    involved.  —  A    fundamental    and    main 
factor  in  causing  undesirable  changes  in  food  is  the  pres- 
ence and  activity  of  micro-organisms  such  as  the  molds 
and  many  types  of  bacteria.     The  conditions  related  to 
the  control  of  these  minute  and  ever  present  organisms  are 
cleanliness,  moisture,  temperature,  heat,  sunlight,  various 
disinfectants,   and  preservatives.     It  is  not  proposed  to 
treat  each  of  these  conditions  or  factors  separately,  but 
to  show  their  relation  to  different  classes  of  food  materials. 

330.  Moist  foods.  —  Many  foods,  such  as  milk,  meats; 
certain  kinds  of    pastry,  puddings,  and    similar    cookect 
preparations,  and  breads  and  cakes  that  are  stored  in  a 
closed  space  to  prevent  evaporation,  necessarily  contaiii 

343 


344  Principles  of  Human  Nutrition 

an  amount  of  water  that  is  favorable  to  the  inroads  of 
the  low  forms  of  life.  With  such  foods  two  conditions 
determine  the  success  with  which  they  are  held  against 
fungus  or  bacterial  action,  viz.,  cleanliness  and  tempera- 
ture. The  receptacle  of  whatever  kind  in  which  moist 
foods  are  kept  should  be  scrupulously  clean,  that  is,  no 
accumulation  of  dirt,  however  small,  should  be  permitted 
as  a  breeding  place  for  germ  life.  This  is  fundamental. 
The  refrigerator  is  often  neglected  and  does  not  receive 
the  frequent  thorough  cleaning  that  is  necessary  to  the 
best  conditions.  Jars,  cake  boxes  and  other  receptacles 
in  which  bread  and  cake  are  stored,  should  receive  no  less 
careful  attention.  A  low  temperature  is  a  safeguard 
against  the  growth  of  micro-organisms.J  In  a  refrigerator 
where  meat  and  other  perishable  articles  are  kept  the  ice 
supply  should  be  sufficient  to  hold  the  temperature  down 
to  40°  F.  or  less.  This  means  a  larger  ice  box  in  proportion 
to  the  rest  of  the  space  than  is  found  in  some  refrigerators. 

Jars  or  boxes  in  which  bread  and  cake  are  kept  should  be 
located  in  as  cool  a  place  as  possible. 

331.  Dry  foods.  —  These  are  principally  flours,  meals, 
sugar,  dried  and  preserved  meats,  and  dried  fruits.  Some 
of  these  are  immune  to  the  action  of  germ  life  because  of 
the  presence  of  some  substance  like  salt  or  sugar  in  suffi- 
cient concentration  to  act  as  a  germicide.  This  may  be 
true  of  preserved  meats.  The  flours,  meals,  and  dried 
fruits  maintain  a  sound  condition  unless  through  damp- 
ness they  absorb  moisture  beyond  a  safe  proportion. 
/Such  materials  should  be  kept  in  a  dry  place,  well  lighted 
and  well  ventilated,  if  possible.  Fresh  air  and  sunlight, 
even  diffused  light,  are  inimical  to  bacteria  and  similar 


The  Preservation  of  Food  345 

organisms.  Dark  and  unventilated  storerooms  are  not 
desirable. 

332.  The  cellar  as  a  storage  place.  —  The  aim  in  hold- 
ing vegetables  and  fruits  is  to  maintain  them  in  a  fresh, 
crisp  condition  by  preventing  the  evaporation  of  water 
from  their  tissues  and  also  to  defend  them  against  the 
attacks  of  destructive  forms  of  germ  life.  Here  again 
we  see  the  importance  of  cleanliness,  the  right  temperature, 
and  varying  moisture  conditions  according  to  the  kind  of 
material. 

/  The  cellar  is  the  usual  storage  place  for  vegetables  and 
fruits.  The  first  consideration  is  that  it  be  properly  built 
and  drained,  so  that  undue  moisture  may  be  avoided. 
This  means  a  dry  location,  if  possible,  good  cement  walls, 
and  effective  drainage.  As  the  cellar  generally  contains 
the  heating  apparatus,  the  portions  used  for  food  storage 
should  be  separated  from  the  furnace  and  fuel  room  by 
well-built  partitions. 

The  storage  space  should  be  well  ventilated  and  in  the 
main  well  lighted.  An  annual  whitewashing  is  an  effec- 
tive method  of  cleansing  the  walls  and  ceiling. 

For  most  fruits  and  vegetables  the  lower  the  tempera- 
ture at  which  they  are  held,  above  freezing  of  course,  the 
more  completely  are  they  defended  against  molds  and  rots 
and  the  better  they  retain  their  tissue  water.  If  a  cellar 
is  quite  dry,  roots  like  carrots,  parsnips,  and  turnips  should 
be  packed  in  earth  and  sand.  Celery  should  be  treated  in 
the  same  way  with  the  heads  up.  Fruits  should  be  treated 
with  especial  care.  Not  only  should  they  be  kept  cool, 
but  all  diseased  and  imperfect  specimens  should  be  culled 
out.  Small  lots  of  choice  fruit,  apples  and  pears,  are  held 


346  Principles  of  Human  Nutrition 

(much  longer  when  the  individual  fruits  are  wrapped  in 
paper.  Fruits  thus  separated  are  much  less  likely  to 
decay,  and  evaporation  of  moisture  is  somewhat  retarded. 
Cabbage  may  be  packed  in  barrels  or  boxes.  Potatoes 
keep  best  in  a  cool,  dry,  dark  bin.  Pumpkins  and  squashes 
are  stored  most  successfully  on  shelves  either  in  the  cellar 
or  in  upstairs  closets,  where  it  is  dry  and  warm.  A  dry 
and  well-ventilated  cellar  may  be  used  as  a  place  for  stor- 
ing cured  meats  (smoked),  which  are  best  held  in  thin  bags 
hung  from  the  ceiling. 

333.  Canning  and  preserving.  —  The  preservation  of 
food  materials  by  canning  and  preserving  is  effected  iri 
two  general  ways:  (1)  by  the  application  of  boiling  heat 
for  a  sufficient  length  of  time  to  kill  all  germ  life  with  the 
subsequent  sealing  of  the  cooked  material  in  air-tight 
vessels,  and  (2)  by  the  introduction  of  some  substance  like 
sugar  or  certain  chemical  preservatives  that  render  the  j 
vegetable  or  fruit  immune  to  the  attacks  of  germ  life. 

The  home  canning  of  some  vegetables,  for  instance 
tomatoes,  is  successfully  accomplished  with  no  great  diffi- 
culty by  the  mere  application  of  heat.  The  operation 
with  green  corn  and  peas  is  more  precarious,  the  difficulty 
being  by  home  methods  to  render  these  sterile  without 
carrying  the  cooking  process  so  far  as  to  injure  their  flavor. 
There  has  existed  a  tendency  to  remedy  the  defects  of  the 
home  canning  of  vegetables  by  the  use  of  some  one  of  the 
chemical  preservatives  such  as  benzoic  acid  and  its  com- 
pounds, but  this  practice  is  not  to  be  commended.  As 
before  stated,  it  is  a  debatable  question  whether  the  con- 
tinued use  of  such  substances  in  food  is  not  ultimately 
injurious  to  health. 


The  Preservation  of  Food  347 

In  the  preserving  of  fruits  where  the  sterilization  is  not 
affected  by  heat,  sugar  is  used  in  sufficient  proportions  to 
prevent  fermentation. 

334.  Insects.  —  There  is  more  or  less  IOSSN  of  food 
materials  through  the  depredations  of  insects.  House- 
wives have  often  found  an  insect  infestation  of  foods  a 
troublesome  matter  to  deal  with.  Several  species  of 
weevils  and  beetles  infest  dry  foods,  especially  the  cereal 
preparations  like  flour,  meal,  and  breakfast  foods.  "  An 
ounce  of  prevention  is  worth  a  pound  of  cure,"  so  the  house- 
keeper should  be  careful  not  to  accept  from  the  grocer  any 
food  stuff  containing  insect  life.  In  order  to  exercise  great 
care  in  this  matter,  the  presence  of  larva  and  beetles  may 
be  discovered  by  sifting  flour  or  meal  through  a  sieve  with 
very  fine  meshes. 

When  an  insect  infestation  of  the  pantry  is  discovered, 
then  methods  of  getting  rid  of  it  must  be  considered.  If 
the  amount  of  infested  material  is  small,  then  its  destruc- 
tion or  the  use  of  it  as  food  for  animals  is  the  safest  and 
most  satisfactory  course  to  pursue.  If  a  barrel  of  flour 
or  other  large  bulk  of  ground  cereal  is  found  to. contain 
insect  life,  then  the  remedy  is  likely  to  depend  somewhat 
upon  the  degree  of  fastidiousness  of  the  family. 

Flour  or  meal  cannot  with  certainty  be  freed  from  in- 
sect life  by  the  use  of  a  sieve,  as  the  eggs  and  young  larva 
slip  through  the  finest  meshes.  /Heat  and  disinfection  are 
the  only  sure  means  of  .killing  the  insects^)  Heating  the 
infested  material  in  an  oven  for  a  time  at  the  temperature 
of  125°  to  150°  F.  is  fatal  to  eggs,  larva,  and  perfect  insects, 
f  Disinfection  of  a  barrel  of  flour  or  other  large  quantity  of 
V  prepared  cereal  may  be  accomplished  by  the  use  of  a 


348  Principles  of  Human  Nutrition 

liquid  chemical  known  as  bi-sulfide  of  carbon!  This 
liquid  is  volatile  at  ordinary  temperatures,  and,  as  a  gas,  it 
will  fill  any  space,  provided  a  sufficient  quantity  is  used. 

With  a  barrel  of  flour  a  cup  full  of  bi-sulfide  may  be 
placed  on  top  of  the  flour  in  a  shallow  dish,  and  the 
barrel  tightly  covered,  to  remain  so  for  a  day  or  more. 
Sometimes  it  is  necessary  to  repeat  the  operation.  An 
entire  room  may  be  freed  from  insects  by  placing  in  it  in 
shallow  dishes  bi-sulfide  at  the  rate  of  1  pound  to 
1000  cubic  feet  of  space,  keeping  the  room  tightly  closed. 
The  gas  is  inflammable  and  should  not  be  exposed  to  a  light 
or  other  means  of  ignition.  Its  odor  is  very  disagreeable, 
but  it  all  passes  away  from  food  without  harming  it,  and 
a  slight  inhalation  of  the  gas  does  no  harm. 

It  is  probable  that  many  persons  would  object  to  eating 
food  in  which  dead  insects  are  retained,  therefore  the  infes- 
tation of  a  large  supply  of  food  materials  is  a  somewhat 
serious  matter,  and  great  care  should  be  taken  to  prevent  it. 

DIAGRAMS  OF  CUTS  OF  MEAT  FROM  VARIOUS  ANIMALS 

In  the  subsequent  table  of  composition  of  food  stuffs 
are  given  the  analyses  of  a  great  variety  of  cuts  of  meat. 

The  diagrams1  which  follow  show  very  clearly  the  parts 
of  the  animal  from  which  the  cuts  are  taken.  These  may 
serve  to  aid  the  housewife  in  dealing  wit  Ji  the  meat  market. 

1  Reproduced  from  Bui.  28,  O.E.S.  (revised  edition). 


The  Preservation  of  Food 


349 


FIG.  13.  —  Diagrams  of  cuts  of  beef. 


1.  Neck. 

2.  Chuck. 

3.  Ribs. 

4.  Shoulder  clod. 

5.  Fore  shank. 


6.  Brisket. 

7.  Cross  ribs. 

8.  Plate. 

9.  Navel. 
10.  Loin. 


11.  Flank. 

12.  Rump. 

13.  Round. 

14.  Second  cut  round. 

15.  Hind  shank. 


FIG.  14.  —  Diagrams  of  cuts  of  veal. 


1.  Neck. 

2.  Chuck. 

3.  Shoulder. 

4.  Fore  shank. 


5.  Breast. 

6.  Ribs. 

7.  Loin. 


8.  Flank. 

9.  Leg. 

10.  Hind  shank. 


350 


Principles  of  Human  Nutrition 


FIG.  15.  —  Diagrams  of  cuts  of  lamb  and  mutton. 


1.  Neck. 

2.  Chuck. 


3.  Shoulder. 

4.  Flank. 


5.  Loin. 

6.  Leg. 


FIG.  16.  —  Diagrams  of  cuts  of  pork. 


1.  Head. 

2.  Shoulder. 

3.  Back. 

4.  Middle  cut. 


5.  Belly. 

6.  Ham. 

7.  Ribs. 

8.  Loin. 


CHEMICAL  COMPOSITION  OF  AMERICAN 
FOOD  MATERIALS1 


The  figures  in  black  type  are  the  averages  of  several  analyses  of  the  materials 
of  the  same  definite  character.  The  figures  in  Roman  type  represent  single 
analyses  or  the  averages  of  all  analyses  of  several  groups  of  materials.  The 
estimated  percentages  of  protein  are  also  in  Roman  type. 


FOOD  MATERIALS 

NUMBER  OF 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

f4 

i 

TOTAL  CARBO- 
HYDRATES 

1 

is 

<  D 

>S. 

H« 

|a 

NX  6.25  H 

By  Differ- 
ence 

ANIMAL  FOOD 

BEEF,   FRESH 

Brisket,  medium  fat  : 
Edible  portion  — 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Cal- 
ories 

Average      .... 

3 



54.6 

15.8 

16.0 

38.5 



0.9 

1495 

As  purchased  — 

Average      .... 

3 

33.3 

41.6 

13.0 

12.2 

33.3 



0.6 

1165 

Chuck,  including  shoul- 

der, very  lean  : 

Edible  portion    .     .     . 

1 



73.8 

22.3 

21.3 

3.9 



1.0 

580 

As  purchased      .     .     . 

1 

18.4 

60.2 

18.2 

17.4 

3.2 



0.8 

475 

Chuck,  including  shoul- 

der, lean  : 

Edible  portion  — 

A 

2 

71.3 

30.3 

19.5 

8.3 

1.0 

730 

Average                •     . 
As  purchased  — 

Average      .... 

2 

19.5 

57.4 

16.3 

15.7 

6.6 



0.8 

580 

Chuck,  including  shoul- 

der, medium  fat  : 

Edible  portion  — 

Average     .... 

4 



68.3 

19.6 

18.9 

11.9 



0.9 

865 

As  purchased  — 

Average      .... 

4 

15.3 

57.9 

16.6 

16.0 

10.1 

0.8 

735 

Chuck,  including  shoul- 

der, fat  : 

Edible  portion  — 

Average      .... 

4 



63.3 

18.5 

18.0 

18.8 



0.9 

1135 

As  purchased  — 
Average      .... 

3 

14.7 

53.3 

15.9 

1.5.4 

15.9 



0.7 

965 

Chuck,  including  shoul- 

der, very  fat  : 

Edible  portion  — 
Average      .... 

2 



53.2 

17.3 

16.9 

39.0 



0.9 

1555 

As  purchased  — 
Average      .     ;     .     . 

3 

32.8 

40.8 

13.3 

13.0 

33.7 



0.7 

1205 

iFrom  Bui.  28,  O.E.S.  (Revised  edition). 

351 


352 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OF  1 

ANALYSES 

1 

PH 

WATER 

PROTEIN 

ft 

TOTAL  CARBO- 
HYDRATES 

1 

< 

• 

Sg 
<  & 

*1 

H 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Chuck,  including  shoul- 
der, all  analyses  : 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Cal- 
ories 

Edible  portion    .     .     . 

13 



65.0 

19.2 

18.7 

15.4 



0.9 

1005 

As  purchased      .     .     . 

12 

17.3 

54.0 

15.8 

15.5 

12.5 



0.7 

820 

Chuck  rib,  very  lean  : 

Edible  portion   .     .     . 

1 



75.8 

22.2 

21.7 

1.4 

' 

1.1 

470 

As  purchased      .     .     . 

1 

16.7 

63.1 

18.6 

18.1 

1.2 



0.9 

395 

Chuck  rib,  lean  : 

Edible  portion  — 

Average      .... 

11 



71.3 

19.5 

194 

8.3 



1.0 

715 

As  purchased  — 

Average      .... 

11 

23.7 

55.1 

15.1 

15.0 

6.4 



0.8 

550 

Chuck  rib,  medium  fat  : 

Edible  portion  — 

Average      .     . 

7 



62.7 

18.5 

18.3 

18.0 



1.0 

1105 

As  purchased  — 

Average      .... 

7 

16.3 

52.6 

15.5 

15.3 

15.0 



0.8 

920 

Chuck  rib,  fat  : 

Edible  portion  — 

Average      .... 

2 



52.0 

16.5 

16.1 

31.1 



0.8 

1620 

As  purchased  — 

Average      .... 

2 

10.2 

46.8 

14.8 

144 

27.9 



0.7 

1455 

Chuck  rib,  all  analyses  : 

Edible  portion   .     .     . 

21 



66.8 

19.0 

18.8 

13.4 



1.0 

920 

As  purchased 

21 

19.1 

53.8 

15.3 

15.2 

11.1 



0.8 

755 

Chuck,  free  from  all  vis- 

ible fat   .     .     .     . 

1 



74.1 

22.6 

22.0 

2.8 



1.1 

540 

Flank,  very  lean  : 

Edible  portion  — 

v 

Average      .... 

3 



70.7 

25.9 

24.8 

3.3 



1.2 

620 

As  purchased  — 

Average     .... 

3 

3.5 

68.2 

24.9 

23.9 

3.3 



1.1 

605 

Flank,  lean  : 

Edible  portion  — 

Average      .... 

3 



67.8 

20.8 

19.9 

11.3 



1.0 

865 

As  purchased  — 

Average     .... 

3 

1.4 

66.9 

20.5 

19.7 

11.0 



1.0 

845 

Chemical  Composition,  American  Food  Materials    353 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


F00D  MATERIALS 

NUMBER  OF 
ANALYSES 

I 

WATER 

PROTEIN 

ft 

fc 

TOTAL  CARBO- 
HYDRATES 

1 

>  o 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Flank,  medium  fat  : 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

5 



60.2 

18.9 

17.9 

21.0 



0.9 

1240 

As  purchased  — 

Average      .... 

5 

10.2 

54.0 

17.0 

16.1 

19.0 



0.7 

1115 

Flank,  fat  : 

Edible  portion  — 

Average      .... 

3 

t  

54.2 

17.1 

16.6 

28.4 



0.8 

1515 

As  purchased  — 

Average      .... 

3 

3.3 

52.4 

16.5 

16.2 

27.3 



0.8 

1460 

Flank,  very  fat  : 

Edible  portion  — 

Average      .... 

2 



34.7 

14.0 

12.8 

51.8 



0.7 

2445 

As  purchased  — 

Average      .... 

2 

6.0 

33.0 

13.2 

12.0 

48.3 



0.7 

2275 

Flank,  all  analyses  : 

Edible  portion   . 
As  purchased      .     . 

16 
16 

5.5 

59.3 
56.1 

19.6 
18.6 

18.7 
17.7 

21.1 
19.9 



0.9 
0.8 

1255 
1185 

Loin,  very  lean  : 

Edible  portion  — 
Average      .... 

3 



70.8 

24.6 

24.2 

3.7 



1.3 

615 

As  purchased  — 
Average      .... 

3 

23.0 

54.6 

18.8 

18.5 

3.0 



0.9 

475 

Loin,  lean: 

Edible  portion  — 
Average      .... 

12 



67.0 

19.7 

19.3 

12.7 



1.0 

900 

As  purchased  — 
Average      .... 

11 

13.1 

58.2 

17.1 

16.7 

11.1 



0.9 

785 

Loin,  medium  fat  : 

Edible  portion  — 
Average      .... 

32 



60.6 

18.5 

18.2 

20.2 



1.0 

1190 

As  purchased  — 
Average      .... 

32 

13.3 

52.5 

16.1 

15.8 

17.5 



0.9 

1040 

Loin,  fat: 

Edible  portion  — 
Average      .... 

6 



54.7 

17.5 

16.8 

27.6 



0.9 

1490 

2A 


354 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF  1 
1  .  ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

1 

FUEL  VALUE 
PER  POUND 

N  X  6.25 

J« 

58 

r 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Loin,  fat  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

6 

10.2 

49.2 

15.7 

15.0 

24.8 



0.8 

1305 

Loin,  very  fat  : 

Edible  portion  — 

Average      .... 

3 



49.7 

17.8 

17.1 

32.3 



0.9 

1695 

As  purchased  — 

Average      .... 

3 

9.7 

44.9 

16.0 

15.5 

29.1 



0.8 

1525 

Loin,  all  analyses  : 

Edible  portion    .     .     . 

56 



61.3 

19.0 

18.6 

19.1 



1.0 

1155 

As  purchased      .     .     . 

55 

13.3 

52.9 

16.4 

16.0 

16.9 



0.9 

1020 

Loin,   boneless  strip,   as 

purchased  :  l 

Average      .... 

6 



66.3 

17.8 

16.2 

16.7 



0.8 

1035 

Loin,  sirloin  butt,  as  pur- 

chased :  i 

Average      .... 

6 



62.5 

19.7 

18.9 

17.7 



0.9 

1115 

Loin,  porterhouse  steak  :l 

Edible  portion   . 

7 



60.0 

21.9 

18.6 

20.4 



1.0 

1270 

As  purchased 

7 

12.7 

52.4 

19.1 

16.2 

17.9 



0.8 

1110 

Loin,  sirloin  steak:  l 

Edible  portion   .     .     . 

21 



61.9 

18.9 

18.6 

18.5 



1.0 

1130 

As  purchased      .     . 

21 

12.8 

54.0 

16.5 

16.2 

16.1 



0.9 

985 

Loin,  top  of  sirloin  :  l 

Edible  portion    .     .     . 

1 



42.2 

13.8 

13.3 

43.7 



0.8 

2100 

As  purchased      ... 

1 

3.2 

40.9 

13.3 

12.9 

42.3 



0.7 

2030 

Loin,  tenderloin,  as  pur- 

chased :  i 

Average      .... 

6 



59.2 

16.2 

15.6 

24.4 



0.8 

1330 

Loin  trimmings  :  l 

Edible  portion    .     .     . 

6 



55.0 

16.9 

16.2 

28.0 



0.8 

1495 

As  purchased      .     .     . 

6 

48.8 

27.9 

8.5 

8.2 

14.7 



0.4 

780 

Loin,  free  from  all  visible 

fat      . 

2 

74  0 

00    -I 

&i  fy 

31 

10 

fZAfl 

Navel,  very  lean  : 

<  rr.U 

44.  L 

&L  .  I 

.1 

.2 

54  U 

Edible  portion    .     .     . 

1 



68.6 

30.7 

29.4 

0.6 



1.4 

595 

loin  parts  are  included  under  analyses  of  "loin.' 


Chemical  Composition,  American  Food  Materials   355 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FQOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

3 

TOTAL  CARBO- 
HYDRATES 

1 

go 

SB 
>g 

33 
£s 

N  X6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Navel,  very  lean  —  Con- 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

tinued 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

As  purchased      .     .     . 

1 

2.9 

66.6 

29.8 

28.5 

0.6 



1.4 

580 

Navel,  medium  fat  : 

Edible  portion    .     .     . 

1 



47.6 

15.6 

15.1 

36.5 



0.8 

1830 

As  purchased      .     .     . 

1 

11.4 

42.2 

13.8 

134 

32.3 



0.7 

1620 

Neck,  very  lean: 

Edible  portion  — 

Average      .... 

3 



73.2 

22.5 

22.5 

3.2 



1.1 

555 

As  purchased  — 

Average      .... 

3 

44.3 

40.7 

12.5 

12.2 

2.2 



0.6 

325 

Neck,  lean: 

Edible  portion  — 

Average      .... 

2 



70.1 

21.4 

20.5 

8.4 



1.0 

750 

As  purchased  — 

Average      .... 

2 

29.5 

49.5 

15.1 

144 

5.9 



0.7 

530 

Neck,  medium  fat  : 

Edible  portion  — 

Average      .... 

10 



63.4 

20.1 

19.2 

16.5 



0.9 

1070 

As  purchased  — 

Average      .... 

10 

27.6 

45.9 

14.5 

13.9 

11.9 



0.7 

770 

Neck,  all  analyses  : 

Edible  portion   . 

15 



66.3 

20.7 

20.0 

12.7 



1.0 

920 

As  purchased      .     .     . 

15 

31.2 

45.3 

14.2 

13.6 

9.2 



0.7 

650 

Plate,  very  lean  : 

Edible  portion  — 

Average      .... 

3 



69.1 

22.8 

22.1 

7.7 



1.1 

750 

As  purchased  — 

Average           .     .     . 

3 

37.4 

43.0 

13.6 

13.2 

5.7 



0.7 

495 

Plate,  lean: 

Edible  portion  — 
Average      .... 

3 



65.9 

15.6 

14.6 

18.8 



0.7 

1085 

As  purchased  — 
Average      .... 

3 

17.3 

54.4 

13.0 

12.2 

15.5 



1.6 

895 

Plate,  medium  fat  : 

Edible  portion  — 
Average      .... 

7 



54.4 

16.5 

15.7 

29.1 



0.8 

1535 

356 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF  1 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

a 

go 

j  fc 

1 
X 
fc 

If 

pq 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Plate,  medium  fat  — 
Continued 
As  purchased  — 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average     .... 

7 

16.5 

45.3 

13.8 

13.1 

24.4 



0.7 

1285 

Plate,  fat  : 

Edible  portion  — 

Average 

3 



45.2 

14.6 

14.2 

39.8 



0.8 

1950 

As  purchased  — 

Average      .... 

3 

16.0 

38.0 

12.2 

11.9 

33.5 



0.6 

1640 

Plate,  very  fat  : 

Edible  portion   .     .     . 

1 



34.6 

10.6 

9.8 

55.1 



0.5 

2520 

As  purchased      .     . 

1 

9.0 

31.4 

9.7 

8.9 

50.2 



0.5 

2300 

Plate,  all  analyses  : 

Edible  portion    . 

17 



56.3 

16.8 

16.0 

26.9 



0.8 

1450 

As  purchased      .     .     . 

17 

19.8 

44.4 

13.1 

12.5 

22.7 



0.6 

1200 

Ribs,  very  lean  : 

Edible  portion  — 

Average      .... 

4 



70.9 

25.0 

244 

3.5 



1.2 

615 

As  purchased  — 

Average      .... 

4 

23.3 

54.2 

19.4 

18.9 

2.7 



0.9 

475 

Ribs,  lean: 

Edible  portion  — 

Average      .... 

6 



67.9 

19.6 

19.1 

12.0 



1.0 

870 

As  purchased  — 

Average      .... 

6 

22.6 

52.6 

15.2 

14.8 

9.3 



0.7 

675 

Ribs,  medium  fat  : 

Edible  portion  — 

Average      .... 

15 



55.5 

175 

17.0 

26.6 



0.9 

1450 

As  purchased  — 

Average      .... 

15 

20.8 

43.8 

13.9 

13.5 

21.2 



0.7 

1155 

Ribs,  fat  : 

Edible  portion  — 

Average      .... 

9 



48.5 

15.0 

15.2 

35.6 



0,7 

1780 

As  purchased  — 

Average      .     .     ."    . 

8 

16.8 

39.6 

12.7 

12.4 

30.6 



0.6 

1525 

Ribs,  very  fat  : 

Edible  portion    .     .     . 

1 



45.9 

14.6 

14.8 

38.7 



0.6 

1905 

As  purchased      .     .     . 

1 

6.4 

42.9 

13.7 

13.9 

36.2 



0.6 

1780 

Chemical  Composition,  American  Food  Materials  357 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

H 

s§ 
>! 
g§ 

£§ 

3 

«O 

X 

z 

fi. 

Sl 
& 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Ribs, all  analyses  : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Edible  portion   .     .     . 

35 



57.0 

17.8 

17.5 

24.6 



0.9 

1370 

As  purchased      .     .     . 

34 

20.1 

45.3 

14.4 

13.9 

20.0 



0.7 

1110 

Rib  rolls,  very  lean,  as 

purchased  : 

Average      .... 

2 



73.7 

20.8 

20.3 

5.0 



1.0 

600 

Rib  rolls,   lean,  as  pur- 

chased : 

Average      .... 

3 



69.0 

20.2 

19.5 

10.5 



1.0 

820 

Rib  rolls,  medium  fat,  as 

purchased  : 

Average     .... 

4 



63.9 

19.3 

18.5 

16.7 



0.9 

1065 

Rib  rolls,   fat,  as  pur- 

chased : 

Average      .... 

2 



51.5 

17.2 

16.4 

31.3 



0.8 

1640 

Rib  rolls,  all  analyses,  as 

purchased   . 

11 



64.8 

19.4 

18.8 

15.5 



0.9 

1015 

Rib  trimmings,  all  anal- 

yses: 
Edible  portion  — 
Average      .... 

11 

_ 

54.7 

16.9 

16.1 

28.4 

0.8 

1515 

As  purchased  — 
Average      .... 

11 

34.1 

35.7 

11.0 

10.5 

19.2 

0.5 

1015 

Ribs,  cross,  very  lean  : 
Edible  portion   .     .     . 
As  purchased 

1 
1 

12.8 

65.8 
57.4 

18.0 
15.6 

18.4 
16.1 

14.9 
13.0 



0.9 
0.7 

965 
840 

Ribs,  cross,  medium  fat  : 
Edible  portion    .     .     . 
As  purchased      .     .     . 

1 
1 

12.2 

43.9 
38.6 

13.8 
12.1 

13.7 
12.0 

41.6 
36.5 



0.8 
0.7 

2010 
1765 

Ribs,  cross,  all  analyses  : 
Edible  portion    .     .     . 
As  purchased      .     .     . 

2 
2 

12.5 

54.9 
48.0 

15.9 
13.8 

16.1 
14.0 

28.2 
24.8 



0.8 
0.7 

1485 
1305 

Round,  very  lean  : 

Edible  portion  — 
Average      .... 

6 



73.6 

22.6 

22.S 

2.8 



1.3 

540 

As  purchased  — 
Average      .... 

6 

10.6 

65.9 

20.2 

19.9 

2.4 



1.2 

476 

358 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF  1 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

£ 

TOTAL  CARBO- 
HYDRATES 

I 

• 
P  o 

<% 
^1 

H« 

l« 

N  X  6.25 

1. 

l! 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Round,  lean  : 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

31 



70.0 

31.3 

21.0 

7.9 



1.1 

730 

As  purchased  — 

Average     .... 

39 

8.1 

64.4 

19.5 

19.2 

7.3 



1.0 

670 

Round,  medium  fat: 

Edible  portion  — 

Average      .     .     .   -. 

18 



65.5 

30.3 

19.8 

13.6 



1.1 

950 

As  purchased  — 

Average      .... 

14 

7.3 

60.7 

19.0 

18.3 

13.8 



1.0 

895 

Round,  fat  : 

Edible  portion  — 

Average      .... 

5 



60.4 

19.5 

19.1 

19.5 



1.0 

1185 

As  purchased  — 

Average      .... 

3 

13.0 

54.0 

17.5 

17.1 

16.1 



0.8 

1005 

Round,  very  fat  : 

Edible  portion  — 

Average      .... 

2 



55.9 

18.3 

17.1 

36.3 



0.8 

1445 

As  purchased  — 

Average      .... 

3 

11.4 

49.6 

16.1 

15.2 

33.1 



0.7 

1375 

Round,  all  analyses: 

Edible  portion    .     .     . 

62 



67.8 

20.9 

20.5 

10.6 



1.1 

835 

As  purchased      .     .     . 

54 

8.5 

62.5 

19.2 

18.8 

9.2 



1.0 

745 

Round,  free  from  all  vis- 

ible fat   .... 

4 



73.5 

23.2 

22.8 

2.5 



1.2 

535 

Round,  second  cut  : 

Edible  portion  — 

Average     .... 

2 



69.8 

30.4 

20.5 

8.6 



1.1 

740 

As  purchased  — 

Average     .... 

2 

19.5 

56.3 

16.4 

16.5 

6.9 



0.9 

595 

Rump,  very  lean  : 

Edible  portion  — 

Average      .... 

4 



71.3 

33.0 

22.5 

5.1 



1.3 

645 

As  purchased  — 

Average     .... 

4 

14.3 

60.9 

19.5 

19.1 

4.6 



1.1 

555 

Rump,  lean  : 

Edible  portion  — 

Average      ... 

4 



65.7 

30.9 

19.6 

13.7 



1.0 

965 

Chemical  Composition,  American  Food  Materials   359 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


h 

0  IB 

PROTEIN 

$ 

H 

SQ 

FOOD  MATERIALS 

W 

0S 

. 

K 

% 

JU 

|| 

1 

:>  D 

II 

C 

W 

\ 

X 

9 

H 

<  g 
offl 

1 

is 

£ 

M 

^ 

fc 

« 

h 

< 

s  * 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Rump,  lean  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

3 

14.0 

56.6 

19.1 

17.5 

11.0 



0.9 

820 

Rump,  medium  fat  : 

Edible  portion  — 

Average      .... 

10 



56.7 

17.4 

16.9 

25.5 



0.9 

1400 

As  purchased  — 

Average      .... 

10 

20.7 

45.0 

13.8 

13.4 

20.2 



0.7 

1110 

Rump,  fat: 

Edible  portion  — 

Average      .... 

5 

—  •  — 

47.1 

16.8 

16.4 

35.7 



0.8 

1820 

As  purchased  — 

Average      .... 

5 

23.0 

36.2 

12.9 

12.6 

27.6 



0.6 

1405 

Rump,  very  fat  : 

Edible  portion   .     .     . 

1 



40.2 

15.0 

14-7 

44.3 

:  — 

0.8 

2150 

As  purchased      .     .     . 

1 

16.2 

33.7 

12.6 

12.3 

37.2 



0.6 

1805 

Rump,  all  analyses  : 

Edible  portion   .     . 

24 



57.9 

18.7 

18.1 

23.1 



0.9 

1325 

As  rnirr»hn<*pH 

23 

19.0 

46.9 

15.2 

1  J  "7 

18.6 

0.8 

1065 

Rump,  free  from  all  vis- 

ible fat 

1 

73  9 

21.2 

21.2 

3.8 

1.1 

555 

Shank,  fore,  very  lean  : 

Edible  portion  — 

Average      .... 

4 



74.4 

22.1 

21.7 

2.8 



1.1 

530 

As  purchased  — 

Average      .... 

4 

44.1 

41.6 

12.3 

12.1 

1.6 



0.6 

295 

Shank,  fore,  lean  : 

Edible  portion  — 

Average     .... 

5 



71.5 

22.0 

21.4 

6.1 



1.0 

665 

As  purchased  — 

Average      .... 

5 

36.5 

45.4 

14.0 

13.6 

3.9 



0.6 

425 

Shank,  fore,  medium  fat  : 

Edible  portion  — 

Average      .... 

5 



67.9 

20.4 

19.6 

11.6 



0.9 

870 

As  purchased  — 

Average      .     .     .     . 

5 

36.9 

42.9 

12.8 

12.3 

7.3 



0.6 

545 

Shank,  fore,  very  fat  : 

Edible  portion   .     .     . 

1 



59.0 

20.1 

18.6 

21.6 



0.8 

1285 

360 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

|  NUMBER  OF 
1  ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

g 

• 
<! 

K 

U>  Q 

1% 
*& 

g« 

£" 

N  X  6.25 

!„• 

as 

r 

ANIMAL  FOOD  —  Continues 

BEEF,  FRESH  —  Continued 

Shank,  fore,  very  fat  — 
Continued 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

As  purchased      .     .     . 

1 

30.9 

40.7 

13.9 

12.9 

14.9 



0.6 

890 

Shank,  fore,  all  analyses  : 

Edible  portion   . 

15 



70.3 

21.4 

20.7 

8.1 



0.9 

740 

As  purchased      .     .     . 

15 

38.3 

43.2 

13.2 

12.7 

5.2 



0.6 

465 

Shank,  hind,  very  lean  : 

Edible  portion   .     .     . 

1 



71.2 

26.6 

25.8 

1.7 



1.3 

565 

As  purchased 

1 

50.0 

35.6 

13.3 

12.9 

0.6 



0.7 

280 

Shank,  hind,  lean: 

Edible  portion  — 

^-^ 

Average      .... 

6 



72.5 

21.9 

21.1 

5.4 



1.0 

635 

As  purchased  — 

Average      .... 

6 

58.5 

30.1 

9.1 

8.8 

2.2 



0.4 

260 

Shank,  hind,  medium  fat  : 

Edible  portion  — 

Average      .... 

6 



67.8 

20.9 

19.8 

11.5 



0.9 

875 

As  purchased  — 

Average     .... 

6 

53.9 

31.3 

9.6 

9.1 

5.3 



0.4 

405 

Shank,  hind,  fat  : 

Edible  portion   .     .     . 

1 



61.4 

20.4 

18.9 

18.8 



0.9 

1170 

As  purchased     .     . 

1 

51.6 

29.7 

9.9 

9.2 

9.1 



0.4 

570 

Shank,  hind,  all  analyses  : 

Edible  portion    .     .     . 

14 



69.6 

21.7 

20.7 

8.7 



1.0 

770 

As  purchased     .     . 

14 

55.4 

31.0 

9.7 

9.3 

3.9 



0.4 

345 

Shoulder  and  clod,  very 

lean  :  1 

Edible  portion  — 

Average      .... 

4 



76.1 

21.3 

21.5 

1.3 



1.1 

450 

As  purchased  — 

Average     .... 

4 

23.3 

58.3 

16.3 

16.5 

1.0 



0.9 

345 

Shoulder  and  clod,  lean  : 

Edible  portion  — 

Average      .... 

5 



73.1 

20.4 

20.4 

5.4 



1.1 

605 

As  purchased  — 

Average     .... 

4 

18.8 

59.4 

16.4 

16.5 

4.4 



0.9 

490 

1  The  "clod"  usually  contains  no  refuse. 


Chemical  Composition,  American  Food  Materials  361 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OF 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

h 

TOTAL  CARBO- 
HYDRATES 

| 

ll 

>& 

j 

w  w 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Shoulder  and  clod,  me- 

dium fat  : 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

14 

:. 

68.3 

19.6 

19.3 

11.3 



1.1 

840 

As  purchased  — 

Average      .... 

12 

16.4 

56.8 

16.4 

16.1 

9.8 



0.9 

720 

Shoulder  and  clod,  fat  : 

Edible  portion  — 

Average      .... 

5 



60.4 

19.5 

18.8 

19.8 



1.0 

1200 

As  purchased  — 

Average      .... 

3 

11.9 

52.8 

17.7 

16.7 

17.7 



0.9 

1075 

Shoulder    and    clod,    all 

analyses  : 

Edible  portion    .     .     . 

28 



68.9 

20.0 

19.7 

10.3 



1.1 

805 

As  purchased 

23 

17.4 

57.0 

16.5 

16.3 

8.4 



0.9 

660 

Shoulder,    free    from   all 

visible  fat    .     .     . 

1 



74.6 

21.6 

21.5 

2.7 



1.2 

515 

Socket  : 

Edible  portion    .     .     . 

1 



57.1 

16.9 

16.7 

25.2 



1.0 

1380 

As  purchased 

1 

35.7 

36.7 

10.8 

10.7 

16.2 

;  — 

0.6 

885 

Forequarter,  very  lean  : 

Edible  portion  — 

Average      .... 

2 



74.1 

'.  22.1 

21.3 

3.6 



1.0 

565 

As  purchased  — 
Average      .... 

2 

30.3 

51.5 

15.4 

14-8 

2.7 



0.7 

400 

Forequarter,  lean: 

Edible  portion  — 
Average      .... 

4 



68.6 

18.9 

18.4 

12.2 



0.8 

865 

As  purchased  — 
Average      .... 

4 

22.3 

53.3 

14.7 

14.3 

9.5 



0.6 

675 

Forequarter,  medium  fat  : 

Edible  portion  — 
Average      .... 

10 



60.4 

17.9 

17.3 

21.4 



0.9 

1235 

As  purchased  — 
Average      .... 

10 

18.7 

49.1 

14.5 

14.0 

17.5 



0.7 

1010 

Forequarter,  fat  : 
Edible  portion    .     .     . 
As  purchased 

1 
1 

21.7 

53.5 
41.9 

15.9 
12.5 

15.8 

30.0 
23.4 



0.7 
0.6 

1560 
1220 

302 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

1 

• 

t>  o 

3B 

^ 
S« 

IB 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Forequarter, very  fat  : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Edible  portion    .     .     . 

1 



44.6 

15.0 

14.0 

40.7 



0.7 

1995 

As  purchased 

1 

12.6 

41.5 

12.4 

18.6 

31.7 



0.6 

1570 

Forequarter,  all  analyses  : 

Edible  portion   .     .     . 

18 



62.5 

18.3 

17.7 

18.9 



0.9 

1135 

As  purchased      .     .     . 

18 

20.6 

49.5 

14.4 

14.1 

15.1 

—  :— 

0.7 

905 

Hind  quarter,  very  lean  : 

Edible  portion  — 

• 

Average     .... 

2 



72.0 

24.0 

23.3 

3.5 



1.2 

595 

As  purchased  — 

^T 

Average     .... 

2 

21.0 

56.9 

19.0 

18.4 

2.8 



0.9 

470 

Hind  quarter,  lean  : 

Edible  portion  — 

Average      .... 

4 



66.3 

20.0 

19.3 

13.4 



1.0 

935 

As  purchased  — 

Average      .... 

4 

16.6 

55.3 

16.7 

16.1 

11.2 



0.8 

785 

Hind    quarter,    medium 

fat: 

Edible  portion  — 

Average     .... 

11 



59.8 

18.3 

17.7 

21.6 



0.9 

1250 

As  purchased  — 

Average     .... 

11 

15.7 

50.4 

15.4 

14.9 

18.3 



0.7 

1060 

Hind  quarter,  fat  : 

Edible  portion   .     .     . 

1 



52.1 

17.7 

16.4 

30.7 



0.8 

1625 

As  purchased      .     .     . 

1 

12.4 

45.6 

15.5 

144 

26.9 



0.7 

1425 

Hind  quarter.all  analyses  : 

Edible  portion   .     .     . 

18 



62.2 

19.3 

18.6 

18.3 



0.9 

1130 

As  purchased      .     .     . 

18 

16.3 

52.0 

16.1 

15.5 

15.4 



0.8 

950 

Sides,  very  lean  : 

Edible  portion  — 

Average     .... 

2 



73.1 

23.0 

22.3 

3.5 



1.1 

575 

As  purchased  — 

Average      .... 

2 

26.0 

54.0 

17.0 

16.5 

2.7 



0.8 

430 

Sides,  lean  : 

Edible  portion  — 

Average     .     .     .     . 

4 



67.2 

19.3 

18.7 

13.2 



0.9 

915 

As  purchased  — 

Average      .... 

4 

19.5 

54.1 

15.5 

15.1 

10.6 



0.7 

735 

Chemical  Composition,  American  Food  Materials   363 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

H 

TOTAL  CARBO- 
HYDRATES 

1 

H  Q 

II 

J 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

BEEF,  FRESH  —  Continued 

Sides,  medium  fat  : 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

11 

•- 

59.7 

18.1 

17.4 

33.0 



0.9 

1365 

As  purchased  — 

Average      .... 

11 

17.4 

49.4 

14.8 

144 

18.1 



0.7 

1040 

Sides,  very  fat  : 

Edible  portion    .     .     . 

1 



47.8 

16.2 

15.1 

36.4 



0.7 

1835 

As  purchased      . 

1 

13.2 

41.5 

14.0 

13.1 

31.6 



0.6 

1595 

Sides,  all  analyses: 

Edible  portion    .     .     . 

18 



62.2 

18.8 

18.1 

18.8 



0.9 

1145 

As  purchased      .     .     . 

18 

18.6 

50.5 

15.2 

14.7 

15.5 



0.7 

935 

Miscellaneous  cuts,  free 

from  all  visible  fat1 

11 



73.8 

22.4 

22.1 

2.9 



1.2 

540 

Clear  fat  

7 

13.4 

4.1 

4.1 

82.1 



0.4 

3540 

Soup  stock    



89.1 

6.8 

1.5 



3.6 

170 

BEEF  ORGANS 

Brain,  edible  portion 

1 



80.6 

8.8 

9.0 

9.3 



1.1 

555 

Heart  : 

Edible  portion  — 

Average      .... 

2 



63.6 

16.0 

16.0 

30.4 



1.0 

160 

As  purchased      .     .     . 

1 

5.9 

53.2 

14.8 

15.3 

24.7 



0.9 

1320 

Kidney  : 

Edible  portion  — 

Average      .     .•    .     . 

3 



76.7 

16.6 

16.9 

4.8 

0.4 

1.3 

530 

As  purchased      .     .     . 

1 

19.9 

63.1 

13.7 

14.1 

1.9 



1.0 

335 

Beef  liver  : 

Edible  portion  — 

Average      .... 

6 



71.3 

30.7 

21.2 

4.5 

1.5 

1.6 

605 

As  purchased      .     .     . 

1 

7.3 

65.6 

20.2 

20.2 

3.1 

2.5 

1.3 

555 

Lungs,  as  purchased 

1 



79.7 

16.4 

16.1 

3.2 



1.0 

440 

Marrow,  as  purchased    . 

1 



3.3 

2.2 

2.6 

92.8 



1.3 

3955 

Sweetbreads,      as     pur- 

chased   .... 

1 



70.9 

16.8 

16.4 

12.1 



1.6 

825 

Suet,  as  purchased  : 

Average      .... 

6 



13.7 

4.7 

4.2 

81.8 



0.3 

3540 

Includes  those  given  under  "chuck,"  "round,"  "loin,"  etc. 


364 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


FOOD  MATERIALS 

NUMBER  OF  1 
ANALYSES 

REFUSE 

I 
£ 

PROTEIN 

fc 

TOTAL  CARBO- 
HYDRATES 

1 

w 

Sg 
>£ 

li 

>o 

<N 
M3 
X 
fc 

1  • 

5§ 
$8 

ANIMAL  FOOD  —  Continued 

BEEF  ORGANS  —  Continued 

Tongue  : 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

3 



70.8 

18.9 

19.0 

9.3 



1.0 

740 

As  purchased  — 

Average     .... 

3 

36.5 

51.8 

14.1 

14.2 

6.7 



0.8 

545 

BEEF,   COOKED 

Cut  not  given,  boiled,  as 

purchased   .     .     . 

1 



38.1 

26.2 

26.1 

34.9 



0.9 

2805 

Scraps,  as  purchased  : 

Average      .... 

3 



23.3 

31.4 

21.6 

51.7 



3.5 

3580 

Roast,  as  purchased  : 

Average      .... 

7 



48.3 

32.3 

21.9 

38.6 



1.3 

1620 

Pressed,  as  purchased     . 

1 



44.1 

23.6 

26.7 

27.7 



1.5 

1610 

Round     steak,     fat     re- 

moved,    as    pur- 

chased : 

Average      .... 

18 



63.0 

37.6 

27.5 

7.7 



1.8 

840 

Sirloin  steak,  baked,  as 

purchased   .     .     . 

1 



63.7 

23.9 

24.7 

10.2 



1.4 

875 

Loin    steak,    tenderloin, 

broiled,  edible  por- 

tion: 

Average      .... 

6 



54.8 

33.5 

23.6 

30.4 



1.3 

1300 

Sandwich  meat,  as  pur- 

chased : 

Average      .... 

3 



58.3 

38.0 

27.9 

11.0 



3.8 

985 

BEEF,   CANNED 

Boiled  beef,  as  purchased 

^  1 



51.8 

25.5 

24-4 

22.5 



1.3 

1425 

Cheek,  ox,  as  purchased 

1 



66.1 

22.2 

22.3 

8.4 



3.2 

765 

Chili-con-carne,   as  pur- 

chased   .... 

1 



75.4 

13.3 

13.3 

4.6 

4.0 

2.7 

515 

Collops,  minced,  as  pur- 

chased . 

1 



72.3 

17.8 

17.9 

6.8 

1.1 

1.9 

640 

Corned  beef  : 

Average      .... 

u 



51.8 

36.3 

25.5 

18.7 



4.0 

1280 

Chemical  Composition,  American  Food  Materials   365 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS 

Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

a 

WATER 

PROTEIN 

3 

1  TOTAL  CARBO- 
HYDRATES 

g 

3 

FUEL  VALUE 
PER  POUND  1 

« 

«6 
X 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

BEEF,  CANNED  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Dried beef,  as  purchased  : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

2 



44.8 

39.2 

38.6 

5.4 



11.2 

960 

Kidneys,  stewed,  as  pur- 

chased : 

Average      .... 

2 



71.9 

18.4 



5.1 

2.1 

2.5 

600 

Luncheon  beef,  as  pur- 

chased   .... 

1 



52.9 

27.6 

26.4 

15.9 



4.8 

1185 

Palates,  ox,  as  purchased  : 

Average      .... 

2 



71.4 

17.8 

17.4 

10.0 



1.2 

755 

Roast  beef  ,  as  purchased  : 

t 

A  vpra  fff* 

j 

58.9 

25.9 

J.J  0 

14.S 



1.3 

1105 

Rump     steak,     as     pur- 

chased   .... 

1 



56.3 

24.3 

23.5 

18.7 



1.5 

1240 

Sweetbreads,      as      pur- 

chased   .... 

1 



69.0 

20.2 

19.5 

9.5 



2.0 

775 

Tails,  ox  : 

Edible  portion    .     .     . 

1 



67.9 

26.3 

24.6 

6.3 



1.2 

755 

As  purchased 

1 

29.7 

47.7 

18.5 

17.3 

4.5 



0.8 

535 

Tongue,  ground,  as  pur- 

chased : 

Average      .... 

6 



49.9 

21.4 

21.0 

25.1 



4.0 

1455 

Tongue,  whole,  as  pur- 

chased : 

Average      .... 

5 



51.3 

19.5 

21.5 

23.2 



4.0 

1340 

Tripe,  as  purchased  : 
Average      .... 

2 



74.6 

16.8 

16.4 

8.5 



0.5 

670 

BEEF,   CORNED   AND 

PICKLED 

Brisket  : 
Edible  portion    .     . 
As  purchased      .     .     . 

1 
1 

21.4 

50.9 
40.0 

18.3 
14.4 

18.7 
14.7 

24.7 
19.4 



5.7 
4.5 

1385 
1085 

Flank  : 

Edible  portion  — 
Average      .... 

2 



49.9 

14.6 

14.2 

33.0 



2.9 

1665 

As  purchased  — 
Average      .... 

2 

12.1 

43.7 

12.9 

12.4 

29.2 



2.6 

1470 

366 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

• 
& 

I 

PROTEIN 

H 

<J 

h 

TOTAL  CARBO- 
HYDRATES 

Bj 

<3 

• 

§1 

^ 

g« 

|s 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

BEEF,  CORNED,  ETC.  —  Con- 

tinued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Plate : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Edible  portion   .     .     . 

1 



40.1 

13.7 

13.3 

41.9 



4.7 

2025 

As  purchased      .     .     . 

1 

14.5 

34.3 

11.7 

114 

35.8 



4.0 

1730 

Rump: 

.Edible  portion  — 

Average      .... 

3 



58.1 

15.3 

15.3 

23.3 



3.3 

1270 

As  purchased  — 

Average      .... 

3 

6.0 

54.5 

14.3 

144 

22.0 



3.1 

1195 

Extra  family  beef  : 

Edible  portion    .     .     . 

1 



37.0 

12.3 

11.8 

47.2 



4.0 

2220 

As  purchased      .     .     . 

1 

10.4 

33.1 

11.1 

10.6 

42.3 



3.6 

1990 

Mess  beef,  salted  : 

Edible  portion  — 

Average     .... 

2 



37.0 

12.6 

12.0 

44.5 



6.5 

2110 

As  purchased  — 

Average     .... 

2 

10.5 

33.0 

11.2 

10.7 

39.9 



5.9 

1890 

Corned  beef,  all  analyses  : 

Edible  portion   .     .     . 

10 



53.6 

15.6 

15.3 

26.2 



4.9 

1395 

As  purchased      .     .     . 

10 

8.4 

49.2 

14.3 

14.0 

23.8 



4.6 

1271 

Spiced    beef,    rolled,    as 

purchased   .     .     . 

1 



30.0 

12.0 

11.8 

51.4 



6.8 

2390 

Tongues,  pickled  : 

Edible  portion  — 

Average     .... 

2 



62.3 

12.8 

12.5 

20.5 



4.7 

1105 

As  purchased  — 

Average     .... 

2 

6.0 

58.9 

11.9 

11.6 

19.2 



4.3 

1030 

Tripe,  as  purchased  : 

Average     .... 

4 



86.5 

11.7 

11.8 

1.2 

0.2 

0.3 

270 

Dried,  salted,  and  smoked 

Edible  portion  — 

Average      .... 

7 



54.3 

30.0 

29.7 

6.5 

(3)0.4 

9.1 

840 

As  purchased  — 

Average     .... 

2 

4.7 

53.7 

26.4 

25.8 

6.9 



8.9 

780 

_  JgjeAL,    FRKHH 

Breast,  very  lean  : 

Edible  portion    .     .     . 

J 



73.2 

23.1 

23.1 

2.5 



1.2 

535 

Chemical  Composition,  American  Food  Materials  367 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

1 
« 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

1 

31 
>I 
§1 

to* 

N  X  6.25 

1. 
BJ 

pq 

ANIMAL  FOOD  —  Continued 

VEAL,  FRESH  —  Continued 

Breast,  very  lean  —  Con- 
tinued 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Cal- 
ories 

As  purchased      .     .     . 

1 

46.8 

38.9 

12.3 

12.S 

1.3 



0.7 

285 

Breast,  lean: 

Edible  portion  — 

Average      .... 

3 



70.3 

21.2 

20.7 

8.0 



1.0 

730 

As  purchased  — 

Average      .... 

3 

23.4 

54.0 

15.7 

16.1 

6.2 



0.7 

560 

Breast,  medium  fat  : 

Edible  portion  — 

A 

5 

66.4 

19.4 

18  8 

13.8 

1.0 

930 

Average      .... 

As  purchased  — 

Average      .... 

5 

20.6 

53.7 

15.6 

14.9 

11.0 



0.8 

740 

Breast,  all  analyses  : 

Edible  portion    .     .     . 

8 



68.2 

20.3 

19.8 

11.0 

1.0 

840 

As  purchased      .     . 

8 

24.5 

51.3 

15.3 

14.8 

8.6 



0.8 

645 

Chuck,  lean: 

Edible  portion    .     .     . 

1 



76.3 



20.6 

1.9 



1.2 

465 

As  purchased      .     .     . 

1 

19.0 

61.8 



16.7 

1.6 



0.9 

380 

Chuck,  medium  fat  : 

Edible  portion  — 

Average      .... 

6 



73.3 

19.7 

19.2 

6.5 



1.0 

640 

As  purchased  — 

Average      .... 

6 

18.9 

59.5 

16.0 

15.6 

5.2 



0.8 

515 

Chuck,  all  analyses  : 

-r-ij-i   i      nrtrtiriri 

7 

73.8 

19.7 

19.4 

5.8 

^_^^ 

1.0 

610 

As  purchased      .     .     . 

7 

19.0 

59^8 

ie!o 

15.7 

4.7 



0.8 

495 

Flank,    medium   fat,    as 

purchased  : 

5 

68.9 

20.5 

19.7 

10.4 

1.0 

820 

Average      » 
Flank,  fat,  as  purchased 

1 



57.0 

18.1 

18.0 

24.1 



0.9 

1355 

Flank,    all    analyses,    as 

purchased   .     .     . 

6 



66.9 

20.1 

19.4 

12.7 



1.0 

910 

Leg,  lean  : 

Edible  portion  — 

Average      .... 

9 



73.5 

21.3 

21.2 

4.1 



1.2 

570 

As  purchased  — 
Average      .... 

9 

9.1 

66.8 

19.4 

19.3 

3.7 



1.1 

520 

368 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

§ 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

at 

ii 

to 

X 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

VEAL,  FRESH  —  Continued 

Leg,  medium  fat  : 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

10 



70.0 

30.3 

19.8 

9.0 



1.3 

755 

As  purchased  — 

Average      .... 

9 

14.3 

60.1 

15.5 

16.9 

7.9 



0.9 

630 

Leg,  all  analyses: 

19 

71  7 

or)  7 

Qf\    C 

fi  7 

1| 

R7O 

As  purchased      .     . 

18 

11.7 

/  X.  / 

63.4 

—  'I.  t 

18.3 

&U.O 

18.1 

D.  i 

5.8 



.  JL 

1.0 

D/  U 

585 

Leg,  cutlets: 

Edible  portion  — 

Average     .... 

3 



70.7 

30.3 

20.5 

7.7 



1.1 

705 

As  purchased  — 

Average      .... 

3 

3.4 

68.3 

30.1 

19.8 

7.5 



1.0 

690 

Loin,  lean: 

Edible  portion  — 

Average      .... 

5 



73.3 

30.4 

19.9 

5.6 



1.3 

615 

As  purchased  — 

Average      .... 

5 

33.0 

57.1 

15.9 

15.6 

4.4 



0.9 

480 

Loin,  medium  fat  : 

Edible  portion  — 

Average      .... 

6 



69.0 

19.9 

19.2 

10.8 



1.0 

835 

As  purchased  — 

Average      .... 

6 

16.5 

57.6 

16.6 

16.0 

9.0 



0.9 

690 

Loin,  fat: 

Edible  portion  — 

Average     .... 

3 



61.6 

18.7 

18.5 

18.9 

;  

1.0 

1145 

As  purchased  — 

Average      .... 

3 

18.3 

50.4 

15.3 

15.1 

15.4 



0.8 

935 

Loin,  all  analyses  : 

Edible  portion   .     .     . 

13 



69.5 

19.9 

19.4 

10.0 



1.1 

790 

As  purchased      .     .     . 

13 

18.9 

56.3 

16.1 

15.7 

8.2 



0.9 

645 

Loin,  with  kidney: 

Edible  portion    .     .     . 

1 



73.3 

14.7 

14.1 

11.8 



0.8 

770 

As  purchased 

1 

9.1 

66.7 

13.4 

12.8 

10.7 



0.7 

700 

Neck: 

Edible  portion  — 

Average      .... 

6 

73.6 

30.3 

19.5 

6.9 



1.0 

670 

Chemical  Composition,  American  Food  Materials   369 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


fe 

PROTEIN 

ss 

i§ 

FOOD  MATERIALS 

if 

«  •< 

1 

I 

CM 

CD 

|g 

n  H 

' 

D<J 

C 

X 

rr  § 

b 

^  ^ 

w  § 

fc 

tf 

& 

£ 

M 

£ 

£ 

<J 

£* 

ANIMAL  FOOD  —  Continued 

VEAL,  FRESH  —  Continued 

Neck:  —  Continued 
As  purchased  — 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average      .... 

6 

31.5 

49.9 

13.9 

13.3 

4.6 



0.7 

455 

Rib,  medium  fat  : 

Edible  portion  — 

Average      .... 

9 



72.7 

20.7 

20.1 

6.1 



1.1 

640 

As  purchased  — 

Average      .... 

9 

25.3 

54.3 

15.5 

15.0 

4.6 



0.8 

480 

Rib,  fat  : 

Edible  portion  — 

Average      .... 

3 

1  

60.9 

18.7 

18.8 

19.3 



1.0 

1160 

As  purchased  — 

Average      

3 

24.3 

46.2 

14.2 

14.2 

14.5 



0.8 

875 

Rib,  all  analyses  : 

Edible  portion    . 

12 



69.8 

20.2 

19.7 

9.4 



1.1 

775 

As  purchased      .     .     . 

12 

25.0 

52.3 

15.2 

14.8 

7.1 



0.8 

580 

Rump  : 

Edible  portion    .     .     . 

1 



62.6 

19.8 

20.1 

16.2 



1.1 

1050 

As  purchased 

1 

30.2 

43.7 

13.8 

14.0 

11.3 



0.8 

735 

Shank,  fore: 

Edible  portion  — 
Average      .... 

6 



74.0 

20.7 

19.8 

5.2 



1.0 

605 

As  purchased  — 

Average      .... 

6 

40.4 

44.1 

12.2 

11.8 

3.1 



0.6 

360 

Shank,  hind,  medium  fat  : 

Edible  portion  — 

Average      .... 

6 



74.5 

20.7 

19.9 

4.6 



1.0 

580 

As  purchased  — 
Average      .... 

6 

62.7 

27.8 

7.7 

7.4 

1.7 



0.4 

215 

Shank,  hind,  fat: 

Edible  portion    . 

1 



68.1 

20.5 

20.0 

10.7 



1.2 

835 

As  purchased      .     .     . 

1 

51.4 

33.1 

10.0 

9.7 

5.2 



0.6 

405 

Shank,  hind,  all  analyses  : 

Edible  portion    . 
As  purchased      .     .     . 

7 
7 

61.1 

73.6 
28.6 

20.7 
8.0 

19.9 

7.7 

5.5 
2.2 



1.0 
0.4 

615 
240 

Shoulder,  lean  : 

Edible  portion  — 
Average      .... 

2 



73.4 

20.7 

20.7 

4.6 



1.3 

580 

370 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

• 
8 

WATER 

PROTEIN 

h 

TOTAL  CARBO- 
HYDRATES 

1 

• 

s§ 

<  & 

>s, 

1" 

N  X  6.25 

4. 

5§ 
>»* 

« 

ANIMAL  FOOD  —  Continued 

VEAL,  FRESH  —  Continued 

Shoulder,    lean  :  —  Con- 
tinued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

A  vf»rn  trp 

2 

18.3 

eo  q 

lit    Q 

1ft  Q 

'{  4 

In 

4.QA 

Shoulder  and  flank,  me- 

t)«f.«9 

J.O*«f 

J.  O.t/ 

O.tf 

•U 

*ou 

dium  fat  : 

Edible  portion  — 

Average      .... 

2 



65.2 

19.7 

19.3 

14.4 



1.1 

975 

As  purchased  — 

Average     .... 

2 

23.0 

50.2 

15.1 

14.9 

11.0 



0.9 

745 

Forequarter  : 

Edible  portion  — 

Average      .... 

6 



71.7 

20.0 

194 

8.0 



0.9 

710 

As  purchased  — 

Average     .... 

6 

24.5 

54.2 

15.1 

14.6 

6.0 



0.7 

535 

Hind  quarter  : 

Edible  portion  — 

Average      . 

6 



70.9 

20.7 

19.8 

8.3 



1.0 

735 

As  purchased  — 

Average      .... 

6 

20.7 

56.2 

16.2 

15.7 

6.6 



0.8 

580 

Side,    with   kidney,    fat, 

and  tallow  : 

Edible  portion  — 

Average      .... 

6 



71.3 

20.2 

19.6 

8.1 



1.0 

715 

As  purchased  — 

Average     .... 

6 

22.6 

55.2 

15.6 

15.1 

6.3 



0.8 

555 

Leg,  hind,  medium  fat: 

Edible  portion  — 

Average      .... 

2 



63.9 

19.2 

18.5 

16.5 



1.1 

1055 

As  purchased  — 

Average     .... 

2 

17.4 

52.9 

15.9 

15.2 

13.6 



0.9 

870 

Leg,  hind,  fat: 

Edible  portion   .     .     . 

1 



54.6 

18.3 

17.1 

27.4 



0.9 

1495 

As  purchased      .     .     . 

1 

13.4 

47.3 

15.8 

14.8 

23.7 



0.8 

1295 

Leg,  hind,  very  fat  : 

Edible  portion   .     .     . 

1 



51.8 

17.6 

17.2 

30.1 



0.9 

1595 

As  purchased      .     .     . 

1 

7.0 

48.2 

16.4 

16.0 

28.0 



0.8 

1485 

Chemical  Composition,  American  Food  Materials  371 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OF 
1  {ANALYSES 

& 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

• 
• 
<! 

FUEL  VALUE 
PER  POUND 

3 

CO 

X 

fc 

IBy  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

VEAL,  FRESH  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Leg, hind,  all  analyses  : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Edible  portion    .     .     . 

4 

:  

58.6 

18.6 

17.8 

22.6 



1.0 

1300 

As  purchased 

4 

13.8 

50.3 

16  0 

15.3 

19.7 

0  9 

I  10Q 

Loin,  without  kidney  and 

XloU 

tallow  : 

Edible  portion  — 

Average      .... 

4 



53.1 

18.7 

17.6 

28.3 



1.0 

1540 

As  purchased  — 

Average     .... 

4 

14.8 

45.3 

16.0 

15.0 

24.1 



0.8 

1315 

Neck: 

Edible  portion    .     .     . 

1 



56.7 

17.7 

17.5 

24.8 



1.0 

1375 

As  purchased      .     .     . 

1 

17.7 

46.7 

14.6 

144 

20.4 



0.8 

1135 

Leg,  free  from  all  visible 

fat,  as  purchased 

1 



72.3 

25.3 

23.6 

2.7 



1.4 

585 

Shoulder  : 

Edible  portion   .     .     . 

1 



51.8 

18.1 

17.5 

29.7 



1.0 

1590 

As  purchased     .     .     . 

1 

20.3 

41.3 

14.4 

14.0 

23.6 



0.8 

1265 

Forequarter  : 

Edible  portion   .     .     . 

1 



55.1 

18.3 

18.1 

25.8 



1.0 

1430 

As  purchased     .     .     . 

1 

18.8 

44.7 

14.9 

14-7 

21.0 



0.8 

1165 

Hind  quarter  : 

Edible  portion   .     .     . 

1 



60.9 

19.6 

19.0 

19.1 



1.0 

1170 

As  purchased      .     .     . 

1 

15.7 

51.3 

16.5 

16.0 

16.1 



0.9 

985 

Side,  without  tallow  : 

Edible  portion  — 

Average      .... 

3 



58.2 

17.6 

17.6 

23.1 



1.1 

1300 

As  purchased  — 

Average     .... 

3 

19.3 

47.0 

14.1 

14.2 

18.7 



0.8 

1055 

jjiAJtB,    romnan 

Chops,  biotted  : 

Edible  portion  — 

Average     .... 

* 



47.6 

21.7 

21.2 

29.9 



1.3 

1665 

As  purchased      .     .     . 

13.5 

40.1 

18.4 

18.5 

26.7 



1.2 

1470 

Cut  not  given,   as  pur- 

chased    .... 

1 



47.1 

23.7 

22.1 

29.4 



1.4 

1680 

Leg,  roast     

1 



67.1 

19.7 

19.4 

12.7 



0.8 

900 

372 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  POOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF  1 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

H 
<j 
h 

TOTAL  CARBO- 
HYDRATES 

a 

•< 

pa 

a 

1* 

10 
<N 

CO 

X 

2 

L 

y 

ANIMAL  FOOD  —  Continued 

i 

LAMB,    CANNED 

Tongue,       spiced       and 
cooked  : 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Edible  portion    . 

1 



67.4 

13.9 

14.3 

17.8 



0.5 

1010 

As  purchased      .     .     . 

1 

2.6 

65.7 

13.5 

13.9 

17.3 



0.5 

980 

MUTTON,  FRESH 

Chuck,  lean  : 

Edible  portion   .     .     . 

1 



64.7 

17.8 

18.1 

16.3 

—  ,  — 

0.9 

1020 

As  purchased 

1 

19.5 

52.1 

14.3 

14.5 

13.1 



0.8 

820 

Chuck,  medium  fat  : 

Edible  portion  — 

Average      .... 

6 



50.9 

15.1 

14.6 

33.6 



0.9 

1700 

As  purchased  — 

Average      .... 

6 

31.3 

39.9 

11.9 

11.5 

26.7 



0.6 

1350 

Chuck,  fat  : 

Edible  portion  — 

Average      .... 

2 



40.6 

13.9 

13.7 

44.9 



0.8 

2155 

As  purchased  — 

Average      .... 

2 

16.5 

33.8 

11.6 

11.5 

37.5 



0.7 

1800 

Chuck,  very  fat  : 

Edible  portion    . 

1 



29.9 

9.6 

9.4 

60.1 



0.6 

2715 

As  purchased      .     .     . 

1 

13.8 

25.8 

8.3 

8.1 

51.8 



0.5 

2340 

Chuck,  all  analyses  : 

Edible  portion   .     .     . 

10 



48.2 

14.6 

14-2 

36.8 



0.8 

1825 

As  purchased      .     .     . 

10 

19.4 

38.5 

11.7 

11.4 

30.0 

—  j  — 

0.7 

1485 

Flank,  medium  fat  : 

Edible  portion  -  — 

Average      .     .     .     . 

8 



46.2 

15.2 

14.8 

38.3 



0.7 

1900 

As  purchased  — 

Average      .     .     .     .  ( 

2 

9.9 

39.0 

13.8 

13.6 

36.9 



0.6 

1815 

Flank,  very  fat,  as  pur- 

chased : 

Average     .     .     .     .  : 

2 



28.9 

10.7 

10.7 

59.8 



0.6 

2725 

Flank,  all  analyses  : 

Edible  portion    . 

10 



42.7 

14.3 

14.0 

42.6 



0.7 

2065 

As  purchased      .     .     . 

2 

9.9 

39.0 

13.8 

13.6 

36.9 



0.6 

1815 

Chemical  Composition,  American  Food  Materials   373 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OF 
ANALYSES 

& 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

1 

li 

>& 

l« 

iO 
<N 

CO 

X 

fc 

By  Differ- 
ence 

ANIMAL  FOOD—  Continued 

MUTTON,        FRESH  Con- 

tinued 

Leg,  hind,  lean: 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

3 



67.4 

19.8 

19.1 

13.4 



1.1 

890 

As  purchased  — 

Average      .... 

3 

16.8 

•><;.i 

16.5 

15.9 

10.3 



0.9 

740 

Leg,  hind,  medium  fat  : 

Edible  portion  — 

Average      .... 

11 



63.8 

18.5 

18.2 

18.0 



1.0 

1105 

As  purchased  — 

Average      .... 

11 

18.4 

51.2 

15.1 

14.9 

14.7 



0.8 

900 

Leg,  hind,  fat  : 

Edible  portion    .     .     . 

1 



55.0 

17.3 

17.0 

27.1 



0.9 

1465 

As  purchased 

1 

12.4 

48.2 

15.2 

14.8 

23.8 



0.8 

1290 

Leg,  hind,  all  analyses: 

Edible  portion   .     . 

15 



63.2 

18.7 

18.3 

17.5 



1.0 

1085 

As  purchased      .     . 

15 

17.7 

51.9 

15.4 

15.1 

14.5 



0.8 

900 

Loin,  without  kidney  or 

tallow,  fat  : 

Edible  portion  —  • 

Average      .... 

3 

43.3 



14.7 

14.2 

41.7 



0.8 

3035 

As  purchased  — 

Average      .... 

3 

11.7 

38.3 

13.0 

12.5 

36.8 



0.7 

1795 

Loin,  without  kidney  or 

tallow,  very  fat  : 

Edible  portion    .     .     . 

1 



30.8 

10.6 

10.0 

58.7 



.5 

2675 

As  purchased 

1 

9.0 

28.1 

9.6 

9.1 

53.4 



.4 

2435 

Loin,  without  kidney  or 

tallow,  all  analyses 

Edible  portion    .     .     . 

17 



47.8 

15.5 

15.2 

36.2 



0.8 

1815 

As  purchased      .     .     . 

16 

14.8 

40.4 

13.1 

12.7 

31.5 



0.6 

1575 

Loin,  free  fat  removed    . 

1 



56.5 

23.7 

23.9 

18.5 



1.1 

1225 

Neck,  medium  fat  : 

Edible  portion  — 

Average      .... 

10 



58.1 

16.9 

16.3 

34.6 



1.0 

1355 

As  purchased  — 

Average      .... 

10 

37.4 

43.1 

13.3 

11.9 

17.9 



0.7 

985 

374 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

a 

•< 

Ba 
1% 
*& 

«S 
&" 

N  X  6.25 

I. 

5J 

M 

ANIMAL  FOOD  —  Continued 

MUTTON,  FRESH  —  Con- 

tinued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Neck, very  fat  : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Edible  portion    .     .     . 

1 



42.1 

13.9 

13.6 

43.5 



0.8 

2095 

As  purchased      .     .     . 

1 

16.1 

35.3 

11.7 

11.4 

36.5 



0.7 

1760 

Neck,  all  analyses  : 

- 

Edible  portion   .     .     . 

11 



56.6 

16.7 

16.1 

26.3 



1.0 

1420 

As  purchased      .     .     . 

11 

26.4 

41.5 

12.2 

11.8 

19.6 



0.7 

1055 

Shoulder,  lean: 

Edible  portion   .     .     . 

1 



67.2 

19.5 

18.9 

12.9 



1.0 

905 

As  purchased      .     . 

1 

25.3 

50.2 

14.6 

14.2 

9.6 



0.7 

675 

Shoulder,  medium  fat  : 

Edible  portion  — 

Average      .     .     .     . 

7 



61.9 

17.7 

17.3 

19.9 



0.9 

1170 

As  purchased  — 

Average      .... 

7 

23.5 

47.9 

13.7 

13.4 

15.5 



0.7 

910 

Shoulder,  fat  : 

Edible  portion    .     .     . 

1 

53.0 

16.2 

15.9 

30.3 



0.8 

1580 

As  purchased      .     .     . 

1 

19.5 

42.7 

13.0 

12.8 

24.4 



0.6 

1270 

Shoulder,  very  fat  : 

Edible  portion    .     .     . 

1 



48.4 

15.6 

15.2 

35.6 



0.8 

.1790 

As  purchased      .     . 

1 

18.7 

39.3 

12.7 

124 

28.9 



0.7 

1455 

Shoulder,  all  analyses  : 

Edible  portion    .     .     . 

10 



60.2 

17.5 

17.1 

21.8 



0.9 

1245 

As  purchased      .     .     . 

10 

22.1 

46.8 

13.7 

13.3 

17.1 



0.7 

975 

Forequarter  : 

Edible  portion  — 

Average      .... 

10 



53.9 

15.6 

15.3 

30.9 



0.9 

1595 

As  purchased  — 

Average      .... 

10 

31.3 

41.6 

13.3 

12.0 

34.5 



0.7 

1365 

Hind  quarter  : 

Edible  portion  — 

Average      .... 

10 



54.8 

16.7 

16.3 

38.1 



0.8 

1495 

As  purchased  — 

Average      .... 

10 

17.3 

45.4 

13.8 

13.5 

33.3 



0.7 

1335 

Side,  including  tallow  : 

Edible  portion  — 

Average      .... 

25 



54.3 

16.3 

16.0 

28.9 



0.9 

1530 

Chemical  Composition,  American  Food  Materials   375 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

1  TOTAL  CARBO- 
HYDRATES 

3 

!| 

w  * 

N  X  6.25 

1  By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

MUTTON,   FRESH  (7071- 

'   tinned 

Side,  including  tallow  — 
Continued 
As  purchased  — 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Cal- 
ories 

Average      .... 

35 

18.1 

45.4 

13.0 

12.7 

33.1 

0.7 

1315 

Side.not  including  tallow  : 

Edible  portion  — 

Average      .... 

10 

53.6 

16.3 

15.8 

39.8 



0.8 

1560 

As  purchased  — 

Average      .... 

10 

19.3 

43.3 

13.0 

12.7 

34.0 



0.7 

1355 

Mutton,  leg  roast,  edible 

portion  : 

1 

2 

50.9 

35.0 

25.3 

33.6 

_____ 

1    ** 

1420 

MUTTON,  ORGANS 

Heart,  as  purchased  : 
Average      .... 

3 



69.5 

*TO   »T 

16.9 

-ice 

17.0 

1ft  Q 

13.6 

0.9 

I     0 

845 
440 

Kidneys,  as  purchased    . 

, 

~~~~~i 

/O./ 

J.D.O 

JO.o 

O.Z 

l.O 

Kidney  and  kidney  fat, 
as  purchased    .     . 

1 



18.8 

6.2 

4.8 

76.5 



0.4 

3345 

Kidney  fat,  as  purchased 
Average      .... 

3 



3.4 

1.8 

1.1 

95.4 



0.1 

4060 

Liver,  as  purchased  : 
Average      .... 

3 

61.3 

33.1 



9.0 

5.0 

1.7 

905 

Lungs,  as  purchased  : 
Average      .... 

3 

75.9 

30.3 

£0.1 

3.8 



1.3 

495 

MUTTON,  CANNED 

Corned,  as  purchased 

1 



45.8 

28.8 

27.2 

22.8 



4.2 

1500 

Tongue,  as  purchased     . 

1 



47.6 

24.4 

23.6 

24.0 



4.8 

1465 

PORX,  FRESH 

Chuck  ribs  and  shoulder 

Edible  portion  — 

Average      .... 

3 



51.1 

17.3 

16.9 

31.1 



0.9 

1635 

As  purchased  — 
Average      .... 

3 

18.1 

41.8 

14.1 

13.8 

35.5 



0.8 

1340 

376 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 

Continued 


FOOD  MATERIALS 

NUMBER  OF  1 
ANALYSES 

• 

1 

WATER 

PROTEIN 

£ 

TOTAL  CARBO- 
HYDRATES 

< 

|g 

•«J  t3 
*& 

& 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continrnd 

PORK,  FRESH  —  Continued 

Flank  : 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

3 



59.0 

18.5 

17.8 

22.2 



1.0 

1280 

As  purchased  — 

Average      .... 

3 

18.0 

48.5 

15.1 

14.2 

18.6 



0.7 

1065 

Ham,  fresh,  lean: 

Edible  portion  — 

Average      .... 

2 



60.0 

25.0 

24.3 

14.4 



1.3 

1075 

As  purchased  — 

Average      .... 

2 

0.9 

59.4 

24.8 

24.2 

14.2 



1.3 

1060 

Ham,  fresh,  medium  fat  :  l 

Edible  portion  — 

Average      .... 

10 

—  

53.9 

15.3 

16.4 

28.9 



0.8 

1505 

As  purchased  — 

Average      .... 

10 

10.7 

48.0 

13.5 

14.6 

25.9 



0.8 

1345 

Ham,  fresh,  fat  2 

Edible  portion  — 

Average      .... 

5 



38.7 

12.4 

10.6 

50.0 

:  

0.7 

2345 

As  purchased  — 

Average      .... 

5 

13.3 

33.6 

10.7 

9.2 

43.5 



0.5 

2035 

analyses  :                 '. 

Edible  portion   .     .     J 

17 



50.1 

15.7 

15.6 

33.4 



0.9 

1700 

As  purchased      .     .     J^, 

17 

10.3 

45.1 

1-1.3 

14.1 

29.7 

0.8 

1520 

Ham,    fresh,    visible   fat 

lartrAlv  rpmnv^H 

3 

64.5 

19.2 

10    1 

ii'  o 

0  4 

1040 

Head: 

LO.Jf. 

J.O.* 

U.«f 

Edible  portion  — 

Average      .... 

3 



45.3 

13.4 

12.7 

41.3 



0.7 

1990 

As  purchased  — 

Average      .... 

3 

68.4 

13.8 

4.1 

3.8 

13.8 



0.2 

660 

1  Seven  samples  contained  an  average  of  lecithin  0.32,  gelatinoids  0.8,  and  "flesh 
bases"  1.28  per  cent. 

1  One  sample  contained  lecithin  0.45,  gelatinoids  0.9,  and  "flesh  bases"  0.8  per 
cent. 


Chemical  Composition,  American  Food  Materials   377 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 

Continued 


h 

PROTEIN 

Z 

• 

o 

—     / 

P  a 

FOOD  MATERIALS 

s 

gS 

1 

a 

10 

=1 

CO 

l« 

5  ° 

ai 

•J  £ 

"*,, 

P  * 

fe 

•< 

X 

5 

H  £ 

H 

w  g 

^^ 

tf 

^ 

fe 

PQ 

£ 

< 

£* 

ANIMAL  FOOD  —  Continued 

PORK,  FRESH  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

3 

- 

43.3 

19.5 

16.9 

33.8 



3.3 

1790 

As  purchased      .     .     . 

1 

12.1 

42.3 

18.9 

18.6 

24.0 



3.0 

1365 

Loin  (chops)  ,  lean  : 

Edible  portion    .     .     . 

1 



60.3 

20.3 

19.7 

19.0 



1.0 

1180 

As  purchased 

1 

23.5 

46.1 

15.5 

16.1 

14.5 



0.8 

900 

Loin     (chops),     medium 

fat: 

Edible  portion  1  — 

Average      .... 

19 

—  -  — 

53.0 

16.6 

16.9 

30.1 

1.0 

1580 

As  purchased  — 

Average      .... 

19 

19.7 

41.8 

13.4 

13.5 

34.3 



0.8 

1370 

Loin  (chops),  fat: 

Edible  portion  — 

Average      .... 

4 



41.8 

14.5 

13.1 

44.4 



0.7 

3145 

As  purchased  — 

Average 

4 

16.5 

34.8 

11.9 

10.9 

37.3 



0.6 

1790 

Loin  (chops),  average  all 

analyses  : 

Edible  portion    . 

"24 



50.7 

16.4 

16.4 

32.0 



0.9 

1655 

As  purchased      .     .     . 

24 

19.3 

40.8 

13.2 

13.1 

26.0 



0.8 

1340 

Loin,  tenderloin,  as  pur- 

chased :  2 

Average      .... 

11 



66.5 

18.9 

19.5 

13.0 



1.0 

900 

Middle  cuts  : 

Edible  portion  — 
Average      .... 

3 



48.3 

15.7 

14.8 

36.3 



0.7 

1835 

As  purchased  — 

Average      .... 

3 

19.7 

38.6 

13.7 

12.1 

38.9 



0.7 

1455 

Shoulder  : 

Edible  portion  3  — 

Average      .     .     .     . 

19 



51.3 

13.3 

13.8 

34.3 



0.8 

1690 

1  Eight  samples  contained  an  average  of  lecithin  0.35,  gelatinoids  1.0,  and  "flesh 

bases"  1.5  per  cent. 

2  Eight  samples  contained  an  average  of  lecithin  0.51,  gelatinoids  0.6,  and  "flesh 

bases"  0.9  per  cent. 
3  Eight  samples  contained  an  average  of  lecithin  0.25,  gelatinoids  0.8,  and     flesh 

bases"   1.1  per  cent. 

378 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

H 

• 
< 

go 
§§ 
>& 

li 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

PORK,  FRESH  —  Continued 

Shoulder  —  Continued 
As  purchased  — 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Cal- 
ories 

Average     .... 

19 

13.4 

44.9 

13.0 

12.2 

39.8 



0.7 

1480 

Side,  lard  and  other  fat 

included  : 

Edible  portion  — 

Average      .... 

3 



39.4 

9.4 

8.5 

61.7 



0.4 

3780 

As  purchased  — 

Average      .... 

3 

11.2 

36.1 

8.3 

7.5 

54.8 



0.4 

3465 

Side,  not  including  lard 

and  kidney  : 

Edible  portion  *  — 

Average     .... 

11 



34.4 

9.1 

9.8 

55.3 



0.5 

3505 

As  purchased  — 

Average      .... 

11 

11.5 

30.4 

8.0 

8.6 

49.0 



0.5 

3315 

Clear  backs  : 

Edible  portion  2  — 

Average     .... 

8 



35.1 

6.4 

6.9 

67.6 



0.4 

3970 

As  purchased  — 

Average      .... 

8 

5.7 

33.7 

6.0 

6.4 

63.8 



0.4 

3805 

Clear  bellies  : 

Edible  portion  3  — 

Average      .... 

8 



31.4 

6.9 

7.8 

60.4 



0.4 

3675 

As  purchased  — 

Average      .... 

8 

6.2 

39.5 

6.5 

7.3 

56.6 

_ 

0.4 

3510 

Back  fat,  as  purchased  : 

% 

Average      .... 

3 



7.7 

3.6 

2.3 

89.9 



0.1 

3860 

Belly  fat,  as  purchased  : 

Average     .... 

3 



13.8 

5.3 

4.1 

81.9 



0.3 

3555 

1  Eight  samples  contained  an  average  of  lecithin  0.35,  gelatinoids  1,  and  "flesh 
bases"   1.5  per  cent. 

2  Eight  samples  contained  an  average  of  lecithin  0.21,  gelatinoids  0.6,  and  "flesh 
bases"  0.8  per  cent. 

8  Eight  samples  contained  an  average  of  lecithin  0.18,  gelatinoids  0.6,  and  "flesh 
bases"  0.9  per  cent. 


Chemical  Composition,  American  Food  Materials    379 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

I  NUMBER  OF  1 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

5 

FUEL  VALUE 
PER  POUND 

X 
fc 

fi 

ANIMAL  FOOD  —  Continued 

PORK,  FRESH  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Ham fat,  as  purchased  : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

3 



9.1 

3.5 

2.7 

88.0 



0.2 

3780 

Jowl  fat,  as  purchased  : 

Average      .... 

3 



16.0 

5.9 

6.0 

78.8 



0.2 

3435 

Feet: 

Edible  portion  1  — 

Average      .... 

8 



55.4 

15.8 

17.5 

26.3 

—  

0.8 

1405 

As  purchased  — 

Average      .... 

8 

74.1 

14.3 

4.1 

4.5 

6.9 



0.2 

365 

Tails  : 

Edible  portion  2  — 

Average      .... 

8 



17.4 

4.8 

6.2 

77.1 



0.3 

3340 

As  purchased  — 

Average      .... 

8 

13.3 

15.0 

4.1 

4.6 

66.9 



0.3 

2900 

Trimmings  : 

Edible  portion  — 

Average      .... 

8 



23.3 

5.4 

6.2 

70.2 



0.3 

3060 

As  purchased  — 

Average      .... 

8 

7.4 

21.6 

5.0 

5.7 

65.0 



0.3 

2835 

PORK   ORGANS, 

ETC. 

Brains,  as  purchased 

1 



75.8 

11.7 

12.3 

10.3 



1.6 

655 

Heart,  as  purchased  . 

1 



75.6 

17.1 

17.1 

6.3 



1.0 

585 

Kidneys,  as  purchased  : 
Average      .... 

2 



77.8 

15.5 

16.2 

4.8 



1.2 

490 

Liver,  as  purchased    .     . 

1 



71.4 

21.3 

21.3 

4.5 

1.4 

1.4 

615 

Lungs,  as  purchased  . 

1 



83.3 

11.9 

11.8 

4.0 



0.9 

390 

Marrow,  as  purchased  : 

Average      .... 

6 



14.6 

2.3 

4.2 

81.2 



3 

3470 

Skin,  as  purchased  : 
Average     .... 

7 



46.3 

26.4 

30.4 

22.7 



0.6 

1450 

1  Eight  samples  contained  an  average  of  lecithin  0.32,  gelatinoids  3.5,  and  "flesh 
bases"  2  per  cent. 

2  Eight  samples  contained  an  average  of  lecithin  0.20,  gelatinoids  0.6,  and  "flesh 
bases"  0.6  per  cent.  *  Ash  not  determined. 


380 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMEKICAN  FOOD  MATERIALS 
Continued 


FOOD  MATERIALS 

NUMBER  OF 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

9 

<j 

• 

Sg 

•<   t> 

>& 

«s 

£g 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

PORK,   PICKLED,   SALTED, 

AND  SMOKED 

Ham,  smoked,  lean: 
Edible  portion  — 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average      .... 

3 



53.5 

19.8 

20.2 

20.8 



5.5 

1245 

As  purchased  — 

Average      .... 

3 

11.5 

47.3 

17.5 

17.9 

18.5 



4.9 

1105 

Ham,    smoked,    medium 

fat: 

Edible  portion  — 

Average      .... 

14 



40.3 

16.3 

16.1 

38.8 



4.8 

1940 

As  purchased  :  — 

Average      .     . 

14 

13.6 

34.8 

14.2 

14.0 

33.4 

•  

4.2 

1675 

Ham,  smoked,  fat  : 

Edible  portion  — 

Average      .... 

4 



27.9 

14.8 

16.1 

52.3 



3.7 

2485 

As  purchased  — 

Average      .... 

2 

3.4 

25.2 

12.4 

14.2 

53.7 



3.5 

2495 

Ham,  smoked,  all  anal- 

yses. 

Edible  portion    .     .     . 

21 



39.8 

16.5 

16.7 

38.8 



4.7 

1945 

As  purchased      .     .     . 

19 

12.2 

35.8 

14.5 

14.6 

33.2 



4.2 

1670 

Ham   skin,  as  purchased 

1 



27.2 

15.4 

16.0 

53.7 



3.1 

2555 

Ham,  smoked,  boiled,  as 

purchased  : 

Average     .... 

2 



51.3 

20.2 

20.2 

22.4 



6.1 

1320 

Ham,  smoked,  fried,  as 

purchased   .     .     . 

1 



36.6 

22.2 

244 

33.2 



5.8 

1815 

Ham,  boneless,  raw  : 

Edible  portion  — 

Average     .... 

4 



50.1 

14.9 

15.4 

28.5 



6.0 

1480 

As  purchased  — 

Average     .... 

4 

3.31 

48.5 

14.3 

14.9 

27.5 



5.8 

1425 

Ham,  luncheon,  cooked: 

Edible  portion  — 

Average     .... 

2 

49.2 

22.5 

24.0 

21.0 

~  

5.8 

1305 

1  Refuse,  case. 


Chemical  Composition,  American  Food  Materials   381 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OF  1 

ANALYSES 

REFUSE 

1 

PROTEIN 

ft 

TOTAL  CARBO- 
HYDRATES 

a 

Bo 

It 
^ 

11 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD—  Continued 

PORK,    PICKLED,    SALTED, 

AND  SMOKED  —  Continued 

Ham,    luncheon,    cooked 

—  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

2 

2.1i 

48.1 

22.1 

23.5 

20.6 



5.7 

1280 

Shoulder,    smoked,    me- 

dium fat  : 

Edible  portion  — 

Average      .... 

3 



45.0 

15.9 

15.8 

32.5 



6.7 

1665 

As  purchased  — 

Average      .... 

3 

18.2 

36.8 

13.0 

12.9 

26.6 



5.5 

1365 

Shoulder,  smoked,  fat: 

Edible  portion  — 

Average      .... 

2 



26.5 

15.1 

14.7 

53.6 



5.2 

2545 

As  purchased  — 

Average      .... 

2 

20.0 

21.4 

12.1 

11.8 

42.6 



4.2 

2020 

Shoulder,     smoked,     all 

analyses  : 

Edible  portion   .     .     . 

5 



37.6 

15.5 

15.3 

41.0 



6.1 

2020 

As  purchased      .     .     . 

5 

18.9 

30.7 

12.4 

124 

33.0 



5.0 

1625 

Pigs'  tongues,  pickled  : 

Edible  portion  — 

Average      .... 

2 



58.6 

17.7 

18.0 

19.8 



3.6 

1165 

As  purchased  — 

Average      .... 

2 

3.2 

56.8 

17.1 

17.5 

19.1 



3.4 

1125 

Pigs'  feet,  pickled  : 

Edible  portion  — 

Average      .... 

2 



68.2 

16.3 

16.1 

14.8 



0.9 

930 

As  purchased  — 

Average      .... 

2 

35.5 

44.6 

10.2 

10.0 

9.3 



0.6 

585 

Dry-salted  backs  : 

Edible  portion  — 

Average      .... 

2 



17.3 

7.7 

7.2 

72.7 



2.8 

3210 

As  purchased  — 

Average      .... 

2 

8.1 

15.9 

7.1 

6.5 

66.8 

2.7 

2950 

1  Refuse,  case. 


382 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

s 

•<, 

go 

« 
I! 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD—  Continued 

PORK,   PICKLED,    SALTED, 

AND  SMOKED  —  Continued 

Dry-salted  bellies  : 
Edible  portion  — 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Cal- 
ories 

A  ir<ir«i  trr* 

2 

17.7 

e  4 

fi  7 

72  2 

0     J 

3200 

As  purchased  — 

o«4 

O.  I 

4/v«£ 

O.ft 

Average      .... 

2 

8.2 

16.2 

7.7 

6.2 

66.2 



3.2 

2935 

Salt  pork,   clear  fat,  as 

purchased  : 

Average     .... 

7 



7.9 

1.9 

2.0 

86.2 



3.9 

3670 

Salt  pork,  lean  ends  : 

Edible  portion  — 

Average      .... 

4 



19.9 

8.4 

7.3 

67.1 



5.7 

2985 

As  purchased  — 

Average      .     . 

4 

11.2 

17.6 

7.4 

6.5 

59.6 



5.1 

2655 

Bacon,  smoked,  lean: 

Edible  portion  — 

Average      .... 

2 



31.8 

15.5 

14.6 

42.6 

;  

11.0 

2085 

As  purchased  — 

Average      .... 

2 

17.0 

26.5 

13.0 

12.3 

35.5 



8.7 

1740 

Bacon,  smoked,  medium 

fat: 

Edible  portion  — 

Average      .... 

17 



18.8 

9.9 

9.4 

67.4 



4.4 

3030 

As  purchased  — 

Average      .... 

17 

7.7 

17.4 

9.1 

8.6 

62.2 



4.1 

2795 

Bacon.  Rmftkft^,  all  a.naJ- 

yses: 

Edible  portion    . 

jja_ 

_  —  _  — 

20.2 

10.5 

9.9 

G4.8 

5.1 

2930 

As  purchased      .     .     . 

19 

8.7 

18.4 

9.5 

9.0 

59.4 



4.5 

2685 

Ribs,    cooked,    as    pur- 

chased   .... 

i 



33.6 

24.8 

26.6 

37.6 



2.2 

2050 

Steak,    cooked,    as   pur- 

chased   .... 

i 



33.2 



19.9 

45.4 



1.5 

2285 

PORK,    CANNED 

Brawn,  boars'  brains,  as 

purchased  : 

Average      .... 

2 



49.0 

25.2 

23.4 

23.0 



4.6 

1440 

Chemical  Composition,  American  Food  Materials   383 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

I  NUMBER  OF  1 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

5 

TOTAL  CARBO- 
HYDRATES 

| 

A 

5| 

NX  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

PORK,  CANNED  —  Continued 

Boars'    heads,    as    pur- 
chased : 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average      .... 

2 

—  _ 

55.3 

20.7 

19.2 

22.3 



3.3 

1320 

Ham,    deviled,    as    pur- 

chased : 

Average      .... 

6 



44.1 

19.0 

18.6 

34.1 



3.3 

1790 

SAUSAGE  * 

'Aries: 

Edible  portion    . 

1 

—  -  — 

17.2 

26.8 

24.9 

50.6 



7.3 

2635 

As  purchased 

1 

5.2 

16.3 

25.4 

23.6 

48.0 



6.9 

2495 

Banquet  : 

Edible  portion   .     .     . 

1 



62.7 

18.3 

11.9 

15.7 

—  — 

3.7 

1005 

As  purchased      .     .     . 

1 

1.6 

61.7 

18.0 

17.7 

15.4 



3.6 

985 

Bologna  : 

Edible  portion  — 

Average      .... 

8 



60.0 

18.7 

18.4 

17.6 

0.3 

3.7 

1095 

As  purchased  — 

Average      .... 

4 

3.3 

55.3 

18.2 

18.0 

19.7 



3.8 

1170 

Farmer  : 

Edible  portion    . 

1 

' 

23.2 

29.0 

27.2 

42.0 



7.6 

2310 

As  purchased 

1 

3.9 

22.2 

27.9 

26.2 

40.4 



7.3 

2225 

Frankfort,  as  purchased  : 

Average      .... 

8 



57.2 

19.6 

19.7 

18.6 

1.1 

3.4 

1170 

Holsteiner  : 

Edible  portion    .-    .     . 

1 



25.6 

29.4 

29.4 

37.3 

3.4 

4.3 

2220 

As  purchased      .     .     . 

1 

2.2 

25.1 

28.7 

28.7 

36.5 

3.3 

4.2 

2135 

Lyons,  pure  ham  : 

Edible  portion    .     .     . 

1 



32.5 

32.3 

32.3 

27.2 



8.0 

1750 

As  purchased      .     .     . 

1 

10.0 

29.2 

29.1 

29.1 

24.5 



7.2 

1575 

Pork,  as  purchased  : 

Average      .... 

11 



39.8 

13.0 

12.7 

44.2 

1.1 

2.2 

2125 

1  In  some  cases  the  sum  of  the  percentages  of  water,  protein,  fat,  and  ash  in  sau- 
sage does  not  make  100.  In  such  cases  the  difference  is  estimated  as  carbohydrates. 
There  are,  however,  no  tests  showing  the  presence  of  these,  and  it  may  be  more 
nearly  correct  to  give  no  value  for  carbohydrates. 


384 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

H 

TOTAL  CARBO- 
HYDRATES 

g 

j 

NX  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continuei 

SAUSAGE  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Pork  sausage   meat,    as 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

i        j 

I 

4.R  o 

174, 

17.9 

32.5 

q  4 

1  CQr 

purcnaseQ    .     •     . 
Pork  and  beef  chopped 

j.  /  .4 

O.4 

together,   as   pur- 

i        j 

1 

55  4 

104. 

19.5 

24.1 

1  f) 

1  OOfl 

Salmi  : 

A.U 

JLOoU 

Edible  portion  — 

Average      .... 

2 



30.5 

24.1 

22.6 

39.9 



7.0 

2130 

As  purchased  — 

Average      .... 

2 

9.3 

27.6 

21.8 

20.5 

36.2 



6.4 

1935 

Summer  : 

Edible  portion  — 

A  vprn  crp 

3 

21  2 

2ft  0 

24  6 

44  a 

7  7 

»>*>/»/! 

As  purchased  — 

/vt>.£ 

ivv.U 

*>.f> 

4*4 

Average      .... 

2 

7.0 

20.9 

24.5 

23.0 

42.1 



7.0 

2230 

Tongue,  as  purchased     . 

1 



46.4 

20.1 

17.3 

33.1 



3.2 

1770 

Wienerwurst,     as     pur- 

chased   .... 

1 



43.9 

28.0 



22.1 

1.6 

4.4 

1485 

SAUSAGE,    CANNED 

Beef,  as  purchased     .     . 

1 



59.6 

17.9 

17.8 

20.6 



2.0 

1200 

Bologna,  Italian,  as  pur- 

chased   .... 

1 



42.6 

24.9 

2S.2 

27.8 



6.4 

1635 

Frankfort,  as  purchased 

1 



72.7 

14.9 

14.6 

9.9 



2.8 

695 

Oxford,  as  purchased 

1 



28.9 

9.9 

9.9 

58.5 

0.6 

2.1 

2665 

Pork: 

Edible  portion   .     .     . 

1 



56.6 

16.6 

16.6 

24.8 



2.0 

1355 

As  purchased     .    .     . 

1 

12.61 

49.5 

14.5 

14.6 

21.6 



1.8 

1180 

POULTRY   AND   GAME, 

FRESH 

Chicken,  broilers  : 

Edible  portion  — 

Average     .... 

3 

~—  ~~ 

74.8 

21.5 

21.6 

2.5 



1.1 

505 

Refuse  liquid. 


Chemical  Composition,  American  Food  Materials   385 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


Foop  MATERIALS 

NUMBER  OF  I 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

B 

< 

FUEL  VALUE 
PER  POUND 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

POULTRY  AND  GAME,  FRESH 

—  Continued 

Chicken,  broilers  —  Con- 
tinued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average     .... 

3 

41.6 

43.7 

13.8 

12.6 

1.4 



0.7 

395 

Fowls  :  . 

Edible  portion  — 

Average      .... 

36 



63.7 

19.3 

19.0 

16.3 



1.0 

1045 

As  purchased  — 

Average      .... 

_2fiL 

35.9 

47.1 

,-13.7 

14.0 

13.3 

-"- 

0.7 

775 

Goose,  young: 

Edible  portion    .     .     . 

1 



46.7 

16.3 

16.3 

36.2 



0.8 

1830 

As  purchased      .     .     . 

1 

17.6 

38.5 

13.4 

134 

29.8 



0.7 

1505 

Turkey  : 

Edible  portion  — 

Average      .... 

3 



55.5 

31.1 

20.6 

33.9 



1.0 

1360 

As  purchased  — 

Average      .... 

3 

33.7 

43.4 

16.1 

15.7 

18.4 



0.8 

1075 

Chicken  gizzard,  as  pur- 

chased   .... 

1 



72.5 

24.7 

24.7 

1.4 



1.4 

520 

Chicken  heart,  as  pur- 

chased   .... 

1 



72.0 

20.7 

21.1 

5.5 



1.4 

615 

Chicken    liver,    as    pur- 

chased   .... 

1 



69.3 

22.4 



4.2 

2.4 

1.7 

640 

Goose  gizzard   .... 

1 



73.8 

19.6 

19.4 

5.8 



1.0 

610 

Goose  liver,  as  purchased 

1 



62.6 

16.6 



15.9 

3.7 

1.2 

1050 

Turkey  gizzard,  as  pur- 

chased   .... 

1 



62.7 

20.5 



14.5 

1.2 

1.1 

1015 

Turkey    heart,    as    pur- 

chased   .... 

1 



68.6 

16.8 

17.2 

13.2 



1.0 

870 

Turkey    liver,    as    pur- 

chased      .... 

1 



69.6 

22.9 



5.2 

0.6 

1.7 

655 

POULTRY   AND  GAME, 

COOKED 

Capon  : 

Edible  portion   .     .     . 

1 



59.9 

27.0 

27.3 

11.5 

1.3 

985 

2c 


386 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


.     FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

1 

a 
P  a 

31 
** 

w« 

!§ 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD—  Continued 

POULTRY   AND   GAME, 

COOKED  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Capon —  Continued 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

As  purchased      .     .     . 

1 

10.4 

53.6 

24.2 

24.6 

10.3 



1.2 

885 

Capon,  with  stuffing  : 

Edible  portion   .     .     . 

1 



62.1 

21.8 



10.9 

3.8 

1.4 

935 

As  purchased      .     .     . 

1 

7.7 

57.2 

20.1 

»• 

10.3 

3.5 

1.2 

875 

Chicken,  fricasseed,  edi- 

ble portion       .     . 

1 



67.5 

17.6 



11.5 

2.4 

1.0 

855 

Turkey,      roast,      edible 

portion        .     .     . 

1 



52.0 

27.8 

284 

18.4 

—  ••  — 

1.2 

1295 

Turkey,  roast,  light  and 

dark     meat     and 

stuffing,        edible 

portion  .... 

1 



65.0 



17.1 

10.8 

5.5 

1.6 

870 

POULTRY  AND  GAME, 

CANNED 

Chicken,    sandwich,    as 

purchased        .     . 

1 



46.9 

20.8 

20.5 

30.0 



2.6 

1655 

Turkey,     sandwich,     as 

purchased   .     .     . 

1 



47.4 

20.7 

20.7 

29.2 



2.7 

1615 

Plover,    roast,    as    pur- 

chased   .     .     .     . 

1 



57.7 

22.4 



10.2 

7.6 

2.1 

985 

Quail,  as  purchased    .     . 

1 



66.9 

21.8 



8.0 

1.7 

1.6 

775 

FISH,  FRESH1 

Alewife,  whole  : 

Edible  portion  — 

Average      .... 

2 



74.4 

19.4 

19.2 

4.9 



1.5 

570 

1  A  considerable  number  of  determinations  of  phosphorus,  sulfur,  and  chlorine 
have  been  made  in  the  flesh  of  fresh  fish.  These  are  recorded  in  the  following  table 
in  terms  of  phosphoric  anhydrid  (P2O5),  sulfuric  anhydrid  (SO3),  and  chlorine  (CD, 
and  in  percentages  of  the  total  weight  of  "edible  portion"  or  flesh  : 


Chemical  Composition,  American  Food  Materials  387 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


PHOSPHORIC  ANHYDRID,  STTLFURIC  ANHYDRID,  AND  CHLORINE  IN  SAMPLES  OF 
FRESH  FISH 


PHOSPHORIC  AN- 
HYDRID 

SULFURIC  AN- 
HYDRID 

CHLORINE 

KIND  OF  FISH 

Number 

Number 

Number 

of  Deter- 
mina- 

Average 

of  Deter- 
mina- 

Average 

of  Deter- 
mina- 

Average 

tions 

tions 

tions 

Per  Cent 

Per  Cent 

Per  Cent 

Alewife     .... 

"Qnaa    ' 

1 

0.50 









.nass  : 
Black   .... 

1 

0.44 

1 

0.89 





Striped      .     .     . 

2 

0.48 

1 

0.47 





Blackfiah       .     .     . 

1 

0.52 

1 

0.46 

1 

0.24 

Bluefish    .... 

1 

0.62 









Cod     

2 

0.45 









Eels,  salt  water      . 

1 

0.51 









Flounder       .     .     . 

2 

0.40 

2 

0.42 





Haddock       .     .     . 

2 

0.47 

1 

0.41 





Halibut    .... 

2 

0.44 

1 

0.49 





Herring    .... 

1 

0.55 

1 

0.55 





Mackerel       .     . 

4 

0.56 

2 

0.47 





Muskellunge 

1 

0.52 

1 

0.37 





Perch  : 

White  .... 

2 

0.44 

2 

0.65 





Pike      .... 

1 

0.46 

1 

0.90 





Porgy       .... 

2 

0.59 

1 

0.52 





Red  snapper 

2 

0.47 

2 

0.47 





Salmon     .... 

2 

0.57 

1 

0.61 





Landlocked    . 

2 

0.51 

2 

0.40 





California 

1 

0.69 

1 

0.43 





Shad    

2 

0.60 

1 

0.52 





Sheepshead        .     . 

0.45 

1 

0.48 





Smelt       .... 

0.81 

1 

0.55 





Spanish  mackerel 

0.60 

1 

0.58 





Trout,  brook     .     . 

0.61 

1 

0.48 





Turbot     .... 

0.48 

1 

0.32 





Whitefish      .     .    .. 

0.71 

1 

0.41 

"~  ""*  ' 

388 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OF  1 
ANALYSES 

1 

£ 

WATEK 

PROTEIN 

H 

•<! 
fc 

TOTAL  CARBO- 
HYDRATES 

| 

•q 

sg 
*! 

H« 

IB 

NX  6.25 

|8 

V 

ANIMAL  FOOD  —  Continued 

FISH,  FRESH  —  Continued 

Alewife,       whole  —  Con- 

tinued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

— 

49.5 

37.6 

9.8 

9.7 

2.4 



0.8 

285 

Bass,  black,  whole  : 

Edible  portion  — 

Average     .... 

2 



76.7 

20.6 

204 

1.7 



1.2 

455 

As  purchased  — 

Average     .... 

2 

54.8 

34.6 

9.3 

9.3 

0.8 



0.5 

205 

Bass,  red,  whole  : 

Edible  portion    .     .     . 

1 

81.6 

16.9 

16.7 

0.5 



1.2 

335 

As  purchased      .     .     . 

1 

63.5 

29.8 

6.2 

6.1 

0.2 



0.4 

125 

Bass,  sea,  whole: 

Edible  portion    . 

1 



79.3 

19.8 

18.8 

0.5 



1.4 

390 

As  purchased     .     .  ,  . 

1 

56.1 

34.8 

8.7 

8.3 

0.2 



0.6 

170 

Bass,  striped,  whole  : 

Edible  portion  — 

Average      .... 

6 



77.7 

18.6 

18.3 

2.8 



1.3 

465 

As  purchased  — 

Average      .... 

5 

55.0 

35.1 

8.4 

8.3 

1.1 



0.5 

200 

Bass,     striped,     entrails 

removed,  as  pur- 

chased   .... 

1 

51.2 

37.4 

8.8 

8.7 

2.2 



0.5 

255 

Blackfish,  whole  : 

Edible  portion  — 

Average     .... 

4 



79.1 

18.7 

18.5 

1.3 



1.1 

405 

As  purchased  — 

Average     .... 

2 

60.2 

31.4 

7.4 

7.3 

0.7 



0.4 

165 

Blackfish,     entrails     re- 

moved,    as    pur- 

chased : 

Average     .... 

2 

55.7 

35.0 

8.4 

8.3 

0.5 



0.5 

175 

Bluefish,      entrails      re- 

moved : 

Edible  portion    .     .     . 

1 

J 

78.5 

19.4 

19.0 

1.2 



1.3 

410 

Chemical  Composition,  American  Food  Materials   389 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

• 

< 

li 

«a 

£g 

1C 

01 

<o 
X 

z 

1. 

si 

>i 

pq 

ANIMAL  FOOD  —  Continued 

FISH,  FRESH  —  Continued 

Bluefish,      entrails       re- 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

moved —  Continued 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

As  purchased      .     .     . 

1 

48.6 

40.3 

10.0 

9.8 

0.6 



0.7 

210 

Buffalo  fish,  entrails  re- 

moved : 

Edible  portion   .     .     . 

1 



78.6 

18.0 

17.9 

2.3 



1.2 

430 

As  purchased      .     .     . 

1 

52.5 

37.3 

8.5 

8.5 

1.1 



0.6 

205 

Butter-fish,  whole  : 

Edible  portion    .     .     . 

1 

—  >  — 

70.0 

18.0 

17.8 

11.0 



1.2 

800 

As  purchased      .     .     . 

1 

42.8 

40.1 

10.3 

10.2 

6.3 



0.6 

460 

Catfish  : 

Edible  portion    .     .     . 

1 



64.1 

14.4 

14.4 

20.6 



0.9 

1135 

As  purchased 

1 

19.4 

51.7 

11.6 

11.6 

16.6 



0.7 

915 

Ciscoe,  whole  : 

Edible  portion  — 

Average      .... 

3 



74.0 

18.5 

18.1 

6.8 



1.1 

630 

As  purchased      .     . 

1 

42.7 

43.6 

11.1 

11.0 

2.0 



0.7 

290 

Ciscoe,  entrails  removed, 

as  purchased  : 

Average      .... 

2 

10.1 

65.6 

16.3 

15.9 

7.5 



0.9 

620 

Cod,  whole  : 

Edible  portion  — 

Average      .... 

5 



82.6 

16.5 

15.8 

0.4 



1.2 

325 

As  purchased  — 

Average      .... 

2 

52.5 

38.7 

8.4 

8.0 

0.2 



0.6 

165 

Cod,    dressed,    as    pur- 

chased : 

Average      .... 

3 

29.9 

58.5 

11.1 

10.6 

0.2 



0.8 

215 

Cod,  sections,  edible  por- 

tion: 

Average      .... 

3 



82.5 

16.7 

16.3 

0.3 



0.9 

325 

Cod,  steaks: 

Edible  portion    .     .     . 

1 



79.7 

18.7 

18.6 

0.5 



1.2 

370 

As  purchased      .     .     . 

1 

9.2 

72.4 

17.0 

16.9 

0.5 



1.0 

335 

Cusk,  entrails  removed  : 

Edible  portion    .     .     . 

1 



82.0 

17.0 

16.9 

0.2 



0.9 

325 

390 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


FOOD  MATERIALS 

I  NUMBER  OP 
1  ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

1 

§g 

>! 

H« 

!« 

N  X  6.25 

•it' 

Q§ 
>> 
pq 

ANIMAL  FOOD  —  Continued 

PISH,  FRESH  —  Continued 

Cusk,  entrails  removed  — 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Continued 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

As  purchased      .     .     . 

1 

40.3 

49.0 

10.1 

10.1 

0.1 



0.5 

190 

Eels,    salt    water,    head, 

skin,  and  entrails 

removed  : 

Edible  portion  — 

Average     .... 

3 



71.6 

18.6 

18.3 

9.1 



1.0 

730 

As  purchased  — 

Average      .... 

3 

30.3 

57.3 

14.8 

14.6 

7.3 



0.8 

580 

Flounder,  whole  : 

Edible  portion  — 

Average      .... 

3 



84.3 

14.3 

13.9 

0.6 



1.3 

390 

As  purchased  — 

Average      .... 

3 

61.5 

33.6 

5.4 

6.1 

0.3 



0.5 

115 

Flounder,     entrails     re- 

moved,    as    pur- 

chased   .... 

1 

57.0 

35.8 

6.4 

6.3 

0.3 



0.6 

130 

Haddock,     entrails     re- 

moved : 

Edible  portion  — 

Average     .... 

4 



81.7 

17.3 

16.8 

0.3 



1.3 

335 

As  purchased  — 

Average      .... 

4 

51.0 

40.0 

8.4 

8.2 

0.3 



0.6 

165 

Hake,  entrails  removed  : 

Edible  portion    . 

1 



83.1 

15.4 

15.2 

0.7 



1.0 

315 

As  purchased 

1 

52.5 

39.5 

7.3 

7.2 

0.3 



0.5 

150 

Halibut,   steaks   or  sec- 

tions : 

Edible  portion  — 

Average      .... 

3 



75.4 

18.6 

184 

5.3 



1.0 

565 

As  purchased  — 

Average      .... 

3 

17.7 

61.9 

15.3 

15.1 

4.4 



0.9 

470 

Herring,  whole: 

Edible  portion  — 

Average      .... 

3 

73.5 

19.5 

18.9 

7.1 



1.5 

660 

Chemical  Composition,  American  Food  Materials    391 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

< 

PC. 
§§ 
>& 

K 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

FISH,  FRESH  —  Continued 

Herring,      whole  —  Con- 

tinued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

2 

42.6 

41.7 

11.2 

10.9 

3.9 



0.9 

375 

Kingfish,  whole: 

Edible  portion    .     .     . 

1 



79.2 

18.9 

18.7 

0.9 



1.2 

390 

As  purchased      .     . 

1 

56.6 

34.4 

8.2 

8.1 

0.4 



0.5 

170 

Lamprey,  whole  : 

Edible  portion    .     .     . 

1 

1- 

71.1 

15.0 

14.9 

13.3 



0.7 

840 

As  purchased      .     . 

1 

45.8 

38.5 

8.1 

8.1 

7.2 



0.4 

455 

Mackerel,  whole  : 

Edible  portion  — 

Average      .... 

6 



73.4 

18.7 

18.3 

7.1 



1.2 

645 

As  purchased  — 

Average      .... 

5 

44.7 

40.4 

10.2 

10.0 

4.2 



0.7 

365 

Mackerel,     entrails     re- 

moved,    as    pur- 

chased   .... 

1 

40.7 

43.7 

11.6 

11.4 

3.5 



0.7 

365 

Mullet,  whole  : 

Edible  portion    .     .     . 

1 



74.9 

19.5 

19.3 

4.6 



1.2 

555 

As  purchased 

1 

57.9 

31.5 

8.2 

8.1 

2.0 



0.5 

235 

Muskellunge,  whole  : 

Edible  portion   .     .     . 

1 



76.3 

20.2 

19.6 

2.5 



1.6 

480 

As  purchased      .     .     . 

1 

29.2 

38.7 

10.2 

10.0 

1.3 



0.8 

245 

Perch,  white,  whole  : 

Edible  portion  — 

Average      .... 

2 



75.7 

19.3 

19.1 

4.0 



1.2 

530 

As  purchased  — 

Average      .... 

2 

62.5 

28.4 

7.3 

7.2 

1.5 



0.4 

200 

Perch,    pike     (wall-eyed 

pike)  : 

Edible  portion    .     .     . 

1 



79.7 

18.6 

1S.4 

0.5 



1.4 

365 

As  purchased      .     .     . 

1 

57.3 

34.0 

7.9 

7.9 

0.2 



0.6 

155 

Perch,  yellow,  whole  : 

Edible  portion  — 

Average      .     .     .     . 

2 



79.3 

18.7 

18.7 

0.8 

•     *~~ 

1.2 

380 

392 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS 

Continued 


FOOD  MATERIALS 

NUMBER  OF  1 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

s 

TOTAL  CARBO- 
HYDRATES 

a 

!' 

|3 

N  X  6.25 

PQ 

ANIMAL  FOOD  —  Continued 

FISH,  FRESH  —  Continued 

Perch,   yellow,    whole  — 
Continued 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

As  purchased      .     .     . 

1 

62.7 

30.0 

6.6 

6.7 

0.2 



0.4 

130 

Perch,    yellow,    dressed, 

as  purchased      .     . 

1 

35.1 

50.7 

12.8 

12.6 

0.7 



0.9 

265 

Pickerel,  pike,  whole  : 

Edible  portion  — 

A  v^rn  CTA 

3 

79.8 

18.7 

18  6 

0.5 

1.1 

370 

As  purchased  — 

Average      .... 

2 

47.1 

42.2 

9.9 

9.9 

0.2 



0.6 

190 

Pickerel,  pike,  entrails  re- 

moved as  purchased 

1 

42.7 

45.7 

10.7 

10.7 

0.3 



0.6 

210 

Pike,  gray,  whole  : 

Edible  portion   .     .     . 

1 



80.8 

17.9 

17.8 

0.8 



1.1 

365 

As  purchased     .     .     . 

1 

63.2 

29.7 

6.6 

6.4 

0.3 



0.4 

135 

Pollock,  dressed  : 

i 

76  0 

21  6 

<QI   fy 

0  ft 

1C 

As  purchased      ..:'.,     . 

1 

28.5 

15.5 

U.o 

0.6 



.0 

1.1 

310 

Pompano,  whole: 

Edible  portion  — 

Average      .... 

2 



72.8 

18.8 

18.7 

7.5 



1.0 

665 

As  purchased  — 

Average     .... 

2 

45.5 

39.5 

10.3 

10.2 

4.3 



0.5 

375 

Porgy,  whole  : 

Edible  portion  — 

Average     .... 

3 



75.0 

18.6 

18.5 

5.1 



1.4 

560 

As  purchased  — 

Average     .... 

3 

60.0 

29.9 

7.4 

7.4 

2.1 



0.6 

225 

Red  grouper,  entrails  re- 

moved : 

Edible  portion  — 

Average     .... 

2 



79.5 

19.3 

18.8 

0.6 



1.1 

385 

As  purchased  — 

Average     .... 

2 

55.9 

35.0 

8.5 

8.4 

0.2 



0.5 

165 

Red  snapper,  whole  : 

Edible  portion  — 

Average     .... 

3 



78.5 

19.7 

19.2 

1.0 



1.3 

410 

Chemical  Composition,  American  Food  Materials   393 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

1 

go 

i« 

1 
X 

I, 

a| 

s 

ANIMAL  FOOD  —  Continued 

FISH,  FRESH  —  Continued 

Red    snapper,    whole  — 
Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

2 

46.1 

42.0 

10.8 

10.6 

0.6 



0.7 

225 

Red  snapper,  entrails  and 

gills  removed,   as 

purchased   .     . 

1 

45.3 

43.7 

10.6 

10.0 

0.3 



0.7 

210 

Salmon,  whole: 

Edible  portion  — 

Average      .... 

6 



64.6 

22.0 

21.2 

12.8 



1.4 

950 

As  purchased  — 

m 

Average      .... 

4 

34.9 

40.9 

15.3 

144 

8.9 



0.9 

660 

Salmon,  entrails  removed, 

as  purchased  : 

Average     .... 

2 

29.5 

48.1 

13.8 

13.5 

8.1 



0.8 

600 

Salmon,           landlocked, 

whole,  spent: 

Edible  portion  — 

Average      .... 

4 



77.7 

17.8 

17.8 

3.3 



1.2 

470 

As  purchased  — 

Average      .... 

4 

45.5 

42.3 

9.7 

9.8 

1.8 



0.6 

255 

Salmon,    California,    an- 

terior sections  : 

Edible  portion  — 

Average     .... 

2 



63.6 

17.8 

17.5 

17.8 



1.1 

1080 

As  purchased      .     .     . 

1 

10.3 

57.9 

16.7 

16.1 

14.8 



0.9 

935 

Shad,  whole  : 

Edible  portion  — 

Average      .... 

7 



70.6 

18.8 

18.6 

9.5 



1.3 

750 

As  purchased  — 

Average      .... 

7 

50.1 

35.2 

9.4 

9.2 

4.8 



0.7 

380 

Shad,  roe,  as  purchased 

1 



71.2 

20.9 



3.8 

2.6 

1.5 

600 

Sheepshead,  whole  : 

Edible  portion  — 

Average     .... 

2 



75.6 

20.1 

19.5 

3.7 



1.2 

530 

As  purchased      .     .     . 

1 

66.0 

26.9 

6.6 

6.4 

0.2 



0.5 

130 

Sheepshead,  entrails  re- 

moved, as  purchased 

1 

56.6 

31.2 

9.0 

8.8 

2.9 



0.5 

290 

394 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OP  1 

ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

I 

g« 
§§ 

>£ 

w« 

IB 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

FISH,  FRESH  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Skate, lobe  of  body  : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Edible  portion   .     .     . 

1 



82.2 

18.2 

15.3 

1.4 



1.1 

400 

As  purchased     .     .     . 

1 

51.0 

40.2 

8.9 

7.5 

0.7 



0.6 

195 

Smelt,  whole  : 

Edible  portion  — 

Average      .... 

2 



79.2 

17.6 

17.3 

1.8 



1.7 

405 

As  purchased  — 

Average     .... 

1 

41.9 

46.1 

10.1 

10.0 

1.0 



1.0 

230 

Spanish  mackerel,  whole  : 

Edible  portion   .     .     .  ; 

1 



68.1 

21.5 

21.0 

9.4 



1.5 

795 

As  purchased     .     .     . 

1 

34.6 

44.5 

14.1 

13.7 

6.2 



1.0 

525 

Sturgeon,    anterior    sec- 

tions : 

Edible  portion   .     .     . 

1 



78.7 

18.1 

18.0 

1.9 



1.4 

415 

As  purchased      .     .     . 

1 

14.4 

67.4 

15.1 

154 

1.6 



1.2 

350 

Tomcod,  whole: 

Edible  portion   .     .     . 

1 



81.5 

17.2 

17.1 

0.4 



1.0 

335 

As  purchased     .     .     . 

1 

59.9 

32.7 

6.9 

6.8 

0.2 



0.4 

135 

Trout,  brook,  whole  : 

Edible  portion  — 

Average      .... 

3 



77.8 

19.2 

18.9 

2.1 



1.2 

445 

As  purchased  — 

Average     .... 

3 

48.1 

40.4 

9.9 

9.8 

1.1 



0.6 

230 

Trout,  salmon  or  lake  : 

Edible  portion  — 

Average      .... 

2 



70.8 

17.8 

17.7 

10.3 



12 

765 

As  purchased  — 

Average     .... 

2 

48.5 

36.6 

9.1 

9.2 

5.1 



0.6 

385 

Turbot  : 

Edible  portion   .     .     . 



71.4 

14.8 

12.9 

14.4 



1.3 

885 

As  purchased      .     .     . 

47.7 

37.3 

7.7 

6.8 

7.5 



0.7 

460 

Weakfish,  whole  : 

Edible  portion    .     .     . 



79.0 

17.8 

174 

2.4 



1.2 

430 

As  purchased      .     .     . 

51.9 

38.0 

8.6 

8.4 

1.1 



0.6 

205 

Whitefish,  whole  : 

Edible  portion    .     .     . 



69.8 

22.9 

22.1 

6.5 



1.6 

700 

As  purchased     .     .     . 

53.5 

32.5 

10.6 

10.3 

3.0 



0.7 

325 

Chemical  Composition,  American  Food  Materials    395 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


8. 

PROTEIN 

2  OQ 

«Q 

FOOD  MATERIALS 

ll 

§ 

8 

C0 

|, 

I 

5| 

p 

W 

Q  a 

4  6 

j 

, 

IP 

1 

t 

X 

53 

S1 

1 

Is 

1 

|i 

ANIMAL  FOOD  —  Continued 

FISH,   COOKED 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Bluefish,  cooked,  edible 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

portion   .... 

i 



68.2 

25.9 

^J 

4.5 



1.2 

670 

Spanish  mackerel,  broiled 

Edible  portion   .     .     . 

i 

: 

68.9 

23.7 

SS.^ 

6.5 



1.4 

715 

As  purchased      .     .     . 

i 

7.9 

63.5 

21.8 

«.-# 

5.9 



1.3 

655 

FISH,    PRESERVED    AND 

CANNED  1 

Cod,  salt  :  ' 

0  • 

Edible  portion  — 

Average      .... 

2 



53.5 

25.4 

21.5 

0.3 



24.7  » 

410 

1  A  considerable  number  of  determinations  of  phosphorus,  sulfur,  and  chlorine 
have  been  made  in  the  flesh  of  preserved  and  canned  fish.  These  are  recorded  in 
the  following  table  in  terms  of  phosphoric  anhydrid  (P2O3),  sulfuric  anhydrid  (SO3) 
and  chlorine  (Cl),  and  in  percentages  of  the  total  weight  of  "edible  portion "  or  flesh  : 

PHOSPHORIC  ANHYDRID,  SULFURIC  ANHYDRID,  AND  CHLORINE  IN  SAMPLES  OF 
PRESERVED  AND  CANNED  FISH 


KIND  OF  FISH 

PHOSPHORIC  AN- 
HYDRID 

SULFURIC  AN- 
HYDRID 

CHLORINE 

Number 
of  Deter- 
minations 

Average 

Number 
of  Deter- 
minations 

Average 

Number 
of  Deter- 
minations 

Average 

Cod,  salt       .     .     . 
Cod,  salt,  boneless 
Halibut,  smoked    . 
Herring,  smoked    . 
Mackerel,  salt  .  ,  . 
Salmon,  canned     . 

2 

1 
1 
1 
1 
1 

Per  Cent 
0.25 
0.36 
0.47 
0.84 
0.35 
0.61 

2 

Per  Cent 
0.74 
0.68 
0.44 
1.24 
0.61 
0.44 

2 
1 
1 

1 

Per  Cent 
11.92 
11.19 
8.66 
7.21 

2  It  is  observable  that  in  salt  cod  the  proportion  of  protein  by  difference  is  much 
smaller  than  by  factor.  The  former  value  is  apparently  more  nearly  correct,  and 
has  been  used  in  estimating  the  fuel  value  per  pound. 

*  Two  samples  averaged  23  per  cent  common  salt. 


396 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

1 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

H 

• 
<l 

1§ 

<  P 
*& 

H« 

!« 

U5 
C<J 

(6 
X 
% 

By  Differ- 
ence, 

ANIMAL  FOOD  —  Continued 

FISH,   PRESERVED   AND 

CANNED  —Continued 

Cod,  salt—  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

2 

34.9 

40.3 

19.0 

16.0 

0.4 



18.5 

315 

Cod,  salt,  "boneless": 

Edible  portion  — 

Average      .... 

2 



55.0 

37.3 

25.7 

0.3 



19.01 

490 

As  purchased      .     .     . 

1 

1.6 

54.8 

27.7 

28.6 

0.3 



14.7 

545 

Haddock,  smoked: 

Edible  portion   .     .     . 

1 



72.5 

23.3 

23.7 

0.2 



3.6 

440 

As  purchased      .     .     . 

1 

32.2 

49.2 

15.8 

16.1 

0.1 



2.4 

305 

Haddock,  smoked,  cooked, 

canned,    as    pur- 

chased   .... 

1 



68.7 

22.3 

21.8 

2.3 



7.2 

510 

Halibut,  smoked  : 

Edible  portion  — 

Average      .... 

2 



49.4 

30.7 

20.6 

15.0 



15.02 

1030 

As  purchased  — 

Average      .... 

2 

7.0 

46.0 

19.3 

19.1 

14.0 



13.9 

950 

Herring,  smoked  : 

Edible  portion   .     .     . 

1 



34.6 

36.9 

36.4 

15.8 



13.23 

1355 

As  purchased      .     .     . 

1 

44.4 

19.2 

20.5 

20.2 

8.8 



7.4 

750 

Lamprey,  canned: 

Edible  portion   .     .     . 

1 



63.3 

16.9 



12.2 

3.6 

4.0 

895 

As  purchased      .     .     . 

1 

18.2* 

51.7 

13.8 



10.0 

3.0 

3.3 

735 

Mackerel,    salt,    entrails 

removed  : 

.Edible  portion   .     .     . 

1 



42.2 

21.1 

22.0 

22.6 



13.2  5 

1345 

As  purchased      .     .     . 

1 

22.9 

32.5 

16.3 

17.0 

17.4 



10.2 

1035 

Mackerel,    salt,    canned, 

as  purchased   .     . 

1 



68.2 

19.6 

19.9 

8.7 



3.2 

730 

1  One  sample  contained  19.1  per  cent  common  salt. 

2  One  sample  contained  12.1  per  cent  common  salt. 
8  Contained  11.7  per  cent  common  salt. 

*  Refuse,  oil.  s  Contained  9.2  per  cent  common  salt. 


Chemical  Composition,  American  Food  Materials  397 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

h 

<< 

b 

TOTAL  CARBO- 
HYDRATES 

B 

< 

• 

§1 
^ 

w« 

I" 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

FISH,  PRESERVED   AND 

CANNED  —  Continued 

Mackerel,  salt,  canned  in 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

oil: 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Edible  portion   .     .     . 

1 

—  L_ 

58.3 

25.4 

23.5 

14.1 



4.1 

1065 

As  purchased      .     .     . 

1 

31.5i 

39.9 

17.4 

16.1 

9.7 



2.8 

735 

Mackerel,  salt,  dressed: 

Edible  portion  — 

Average      .... 

2 



43.4 

17.3 

17.3 

26.4 



12.92 

1435 

As  purchased  — 

Average      .... 

2 

19.7 

34.8 

13.9 

13.9 

21.2 



10.4 

1155 

Minogy,  pickled,  canned  : 

Edible  portion    .     .     . 

1 

—  — 

56.5 

22.0 

21.9 

18.6 



3.0 

1195 

As  purchased      .     .     . 

1 

18.73 

46.0 

17.9 

17.8 

15.1 



2.4 

970 

Pilchard     in     tomatoes, 

canned,  Russia,  as 

purchased   .     .     . 

1 



52.7 

27.9 

27.5 

15.8 



4.0 

1185 

Salmon,  canned: 

Edible  portion  — 

Average      .... 

7 



63.5 

21.8 

21.8 

12.1 



2.6 

915 

As  purchased  — 

Average     .... 

3 

14.2 

56.8 

19.5 

19.6 

7.5 



2.0 

680 

Sardines,  canned  : 

Edible  portion  — 

Average      .... 

2 



53.3 

23.0 

224 

19.7 



5.6 

1260 

As  purchased      .     .     . 

1 

5.01 

53.6 

23.7 

24.0 

12.1 



5.3 

950 

Sturgeon,  dried,  Russia  : 

Edible  portion    .     .     . 

1 



50.6 

31.8 

32.2 

9.6 



7.6 

995 

As  purchased      .     .     . 

1 

12.7 

44.1 

27.8 

28.1 

8.4 



6.7 

870 

Sturgeon,  caviare,  pressed 

•' 

Russian,    as   pur- 

chased   .... 

1 



38.1 

30.0 



19.7 

7.6 

4.6 

1530 

Trout,  brook  : 

Edible  portion   .     .     . 

1 



68.4 

22.3 

22.8 

6.1 



3.7 

670 

As  purchased      .     .     . 

1 

3.5 

66.1 

21.5 

20.9 

5.9 

3.6 

650 

1  Refuse,  oil.  2  Contained  10.4  per  cent  common  salt. 

8  Refuse,  liquids. 


398 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


3. 

PROTEIN 

li 

BQ 

• 

3  w 

«J  fc 

FOOD  MATERIALS 

si 

1 

« 

S 

I,' 

>! 

B 

CO 

Q  a 

.««  ft 

j  p. 

2 

I 

1 

X 
fc 

H 

1 

ia 

1 

l§ 

ANIMAL  FOOD  —  Continued 

FISH,  PRESERVED   AND 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

CANNED —  Continued 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Tunney,  as  purchased     . 

i 



72.7 

21.7 

£1.6 

4.1 



1.7 

575 

Tunney,   canned  in  oil, 

Russia  : 

Edible  portion    .     .     . 

i 



51.3 

23.8 



20.0 

0.6 

4.3 

1300 

As  purchased     .     .     . 

i 

16.7  » 

42.7 

20.3 



16.7 



3.6 

1085 

AMPHIBIA 

Frogs'  legs: 

Edible  portion  — 

Average      .... 

3 



83.7 

15.5 

15.1 

0.3 



1.0 

395 

As  purchased  — 

Average     .... 

3 

32.0 

56.9 

10.5 

10.3 

0.1 



0.7 

300 

SHELLFISH,  ETC.,  FRESH2 

Clams,  long,  in  shell  : 

Edible  portion  — 

Average      .... 

4 



85.8 

8.6 



1.0 

3.0 

3.6 

340 

1  Refuse,  oil. 

2  A  considerable  number  of  determinations  of  phosphorus  and  sulfur  have  been 
made  in  the  flesh  of  shellfish.     These  are  recorded  in  the  following  table  in  terms 
of  phosphoric  anhydrid  (P2Os)  and  sulfuric  anhydrid  (SOa)  and  in  percentages  of 
the  total  weight  of  "edible  portion"  or  flesh: 

PHOSPHORIC  ANHYDRID  AND  SULFURIC  ANHYDRID  IN  SAMPLES  OF  SHELLFISH 


KIND  OF  FISH 

PHOSPHORIC  ANHYDRID 

SULFUHIC  ANHYDRID 

Number  of 
Deter- 
minations 

Average 

Number  of 
Deter- 
minations 

Average 

2 
1 
1 
3 
14 
2 
1 

Per  Cent 
0.48 
0.40 
0.53 
0.38 
0.30 
0.48 
0.23 
0.35 

2 
1 
1 
3 

14 
2 
1 
1 

Per  Cent 
0.56 
0.89 
0.26 
0.42 
0.68 
0.49 
0.48 
0.20 

Clams,  round     .... 
Crayfish 

Lobster     

Scallops    

Lobster,  canned     .     .     . 
Oysters,  canned      .     .     . 

Chemical  Composition,  American  Food  Materials   399 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

1 

• 
t>  a 

>1 
|i_ 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

SHELLFISH,   ETC.,  FRESH  

Continued 

Clams,    long,    in    shell  — 
Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

As purchased  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

4 

41.9 

49.9 

5.0 



0.6 

1.1 

1.5 

140 

Clams,  round,  in  shell  : 

Edible  portion   .     .     . 

1 



86.2 

6.5 



0.4 

4.2 

2.7 

215 

As  purchased      .     . 

1 

67.5 

28.0 

2.1 



0.1 

1.4 

0.9 

70 

Clams,   round,   removed 

from  shell,  as  pur- 

chased   .... 

1 



80.8 

10.6 



1.1 

5.2 

2.3 

340 

Crabs,  hardshell,  whole  : 

Edible  portion    . 

1 



77.1 

16.6 



2.0 

1.2 

3.1 

415 

As  purchased 

1 

52.4 

36.7 

7.9 



0.9 

0.6 

1.5 

195 

Crayfish,  abdomen,  whole 

Edible  portion    .     . 

1 



81.2 

16.0 



0.5 

1.0 

1.3 

340 

As  purchased      .     .     . 

1 

86.61 

10.9 

2.1 



0.1 

0.1 

0.2 

45 

Lobster,  whole  : 

Edible  portion  — 

Average      .... 

5 



79.2 

16.4 



1.8 

0.4 

2.2 

390 

As  purchased  — 

Average      .... 

5 

61.7 

30.7 

5.9 



0.7 

0.2 

0.8 

140 

Mussels,  in  shell  : 

Edible  portion    .     .     . 

1 



84.2 

8.7 



1.1 

4.1 

1.9 

285 

As  purchased      .     .     . 

1 

46.7 

44.9 

4.6 



0.6 

2.2 

1.0 

150 

Oysters  in  shell  : 

Edible  portion  — 

Average      .... 

34 



86.9 

6.2 



1.2 

3.7 

2.0 

235 

As  purchased  — 

Average      .... 

34 

81.4 

16.1 

1.2 



0.2 

0.7 

0.4 

45 

Oysters,    solids,    as   pur- 

chased : 

Average      .... 

9 



88.3 

6.0 



1.3 

3.3 

1.1 

230 

Scallops,  as  purchased  : 

Average      .... 

2 

~ 

80.3 

14.8 

~ 

0.1 

3.4 

1.4 

345 

Refuse  of  whole. 


400 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

| 

< 

go 
J  fc 
<  t> 
>o 

PH 
H« 

IB 

k 

o 

X 

z 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

SHELLFISH,   ETC.,  FRESH  

Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Terrapin : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Edible  portion    .     .     . 

1 



74.5 

21.2 

21.0 

3.5 



1.0 

545 

As  purchased      .     .     . 

1 

75.4 

18.3 

5.2 

5.2 

0.9 



0.2 

135 

Turtle,  green,  whole  : 

Edible  portion   .     .     . 

1 



79.8 

19.8 

18.5 

0.5 



1.2 

390 

As  purchased      .     .     . 

1 

76.0 

19.2 

4.7 

44 

0.1 



0.3 

90 

SHELLFISH,  ETC.,  CANNED 

Clams,  long,  as  purchased 

1 



84.5 

9.0 



1.3 

2.9 

2.3 

275 

Clams,    round,    as    pur- 

chased   .... 

1 



82.9 

10.5 



0.8 

3.0 

2.8 

285 

Crabs,  as  purchased  : 

Average      .... 

2 



80.0 

15.8 



1.5 

0.7 

2.0 

370 

Lobster,  as  purchased  : 

Average      .... 

2 



77.8 

18.1 



1.1 

0.5 

2.5 

390 

Oysters,  as  purchased  : 

Average      .... 

4 

—  

83.4 

8.8 



2.4 

3.9 

1.5 

335 

Shrimp,  as  purchased     . 

1 



70.8 

25.4 



1.0 

0.2 

2.6 

520 

gffina- 
Hens,  uncooked  :  * 

Edible  portion  — 

Average      .... 

60 



73.7 

13.4 

14.8 

10.5 



1.0 

720 

As  purchased     .     .     . 

— 

11.22 

65.5 

11.9 

13.1 

9.3 



0.9 

635 

Hens',  boiled  : 

Edible  portion  — 

N 

Average      .... 

19 



73.2 

13.2 

14.0 

12.0 



0.8 

765 

As  purchased     .     .     . 

— 

11.22 

65.0 

1K7 

12.4 

10.7 



0.7 

680 

1  Eggs  are  difficult  of  analysis,  and  the  discrepancy  between  the  protein  by  factor 
and  by  difference  may  be  due  in  part  to  incomplete  determination  of  nitrogen  and 
fat.  It  is  also  probable  that  the  factor  6.25  is  not  correct  for  eggs.  The  value  of 
protein  by  difference  is  perhaps  the  more  nearly  correct  and  has  been  used  in  the 
computation  of  the  fuel  value  per  pound. 

*  Average  percentage  refuse  (shell)  in  34  samples. 


Chemical  Composition,  American  Food  Materials  401 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


b 

O  _, 

PRO 

reii?" 

« 

g« 

FOOD  MATERIALS 

NUMBER 
ANALYSES 

REFUSE 

WATER 

N  X  6.25 

By'  Differ- 
ence 

1 

TOTAL  CAB 

HYDRATE* 

1 

% 
H 

ANIMAL  FOOD  —  Continued 

EGGS  —  Continued 

Hens',  boiled  whites: 
Edible  portion  1  — 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Cal- 
ories 

Average      .... 

11 



86.3 

13.3 

13.0 

0.3 



0.6 

350 

Hens',  boiled  yolks: 

Edible  portion  2  — 

Average      .... 

11 



49.5 

15.7 

16.1 

33.3 



1.1 

1705 

DAIRY  PRODUCTS,  ETC. 

Butter,  as  purchased  3     . 

— 



11.0 

1.0 



85.0 



3.0 

3605 

Buttermilk,  as  purchased 

— 



91.0 

3.0 



0.5 

4?8 

0.7 

165 

Cheese,  American,  pale, 

as  purchased  * 

1 



31.6 

28.8 



35.9 

0.3« 

3.4 

2055 

Cheese,    American,    red, 

as  purchased  * 

1 



28.6 



29.6 

38.3 



3.5 

2165 

Cheese,  Boudon,  as  pur- 

chased ?       ... 

1 



55.2 

15.4 



20.8 

1.68 

7.0 

1195 

Cheese,    California    flat, 

as  purchased    .     . 

4 



34.0 

24.3 



33.4 

4.5 

3.8 

1945 

Cheese,  Cheddar,  as  pur- 

*** 

chased  9       ... 

6 



27.4 

27.7 



36.8 

4.1 

4.0 

2145 

Cheese,  Cheshire,  as  pur- 

chased 10      .     .     . 

1 



37.1 

26.9 



30.7 

0.95 

4.4 

1810 

Cheese,  cottage,  as  pur- 

chased : 

Average 

2 

73.0 

30.9 

/vv.v 



1.0 

4.3 

1.8 

510 

1  The  ash  of  the  whites  of  73  eggs  contained  3.3  per  cent  phosphoric  anhydrid. 

2  The  ash  of  the  yolks  of  73  eggs  contained  57.2  per  cent  phosphoric  anhydrid. 

3  The  averages  given  for  butter,  buttermilk,  cream,  skimmed  milk,  and  whole 
milk  are  assumed  from  the  most  reliable  data  available,  but  are  not  averages  of  all 
analyses.  4   Contained  0.82  per  cent  common  salt. 

5  Lactic  acid.  6  Contained  0.72  per  cent  common  salt. 

7  Contained  3.16  per  cent  common  salt. 

8  Milk  sugar  0.7  per  cent ;   lactic  acid  0.9  per  cent. 

9  One  sample  contained  0.45  per  cent  lactic  acid  and  1.43  per  cent  common  salt. 
1°  Contained  1.69  per  cent  common  salt. 

2D 


402 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

H 
• 
< 

li 

>& 
«« 

!§ 

N  X  6.25 

By  Differ- 
ence 

ANIMAL  FOOD  —  Continued 

DAIRY    PRODUCTS  —  Con- 

tinued 

Cheese,     Crown     brand 
cream,     as     pur- 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

chased  *       .     .     . 

1 



31.4 

5.2 



58.0 

2.2 

3.2 

2585 

Cheese,   Dutch,  as  pur- 

chased : 

Arerage     .... 

3 



35.2 



87.1 

17.7 



10.0 

1435 

Cheese,  Fromage  de  Brie, 

as  purchased  2 

1 



60.2 

15.9 



21.0 

1.4 

1.5 

1210 

Cheese,    full    cream,    as 

purchased  :  3 

A  trAVn  no. 

25 

34.2 

25.9 

33.7 

2.4 

3.8 

1Q?fl 

Average      •     .     •     • 
Cheese,     imitation     full 

*  »f  *MJ 

cream,    Ohio,    as 

purchased   .     .     . 

1 



3-7.9 



25.9 

31.7 



4.5 

1820 

Cheese,     imitation     old 

English,    as    pur- 

chased*      .     .     . 

1 



20.7 

30.1 



42.7 

1.3 

5.2 

2385 

Cheese,    Limburger,    as 

purchased  6      .     . 

1 



42.1 

23.0 



29.4 

0.4 

5.1 

1675 

Cheese,     Neuchatel,     as 

purchased  :  • 

Average     .... 

2 



50.0 

18.7 



27.4 

1.5 

2.4 

1530 

1  Contained  2.72  per  cent  common  salt. 

1  Contained  0.40  per  cent  common  salt. 

»  Four  cheeses  were  analyzed  when  1,  3,  and  5  weeks  old.  The  average  composi- 
tion is  as  follows:  When  7  days  old,  water  35.4,  protein  21.6,  fat  35.8,  carbohy- 
drates 3.9,  and  ash  3.3  per  cent ;  when  21  days  old,  water  34.7,  protein  22.7,  fat  36.6, 
carbohydrates  2.1,  and  ash  3.9  per  cent;  when  35  days  old,  water  34.9,  protein 
23.3,  fat  36.7,  carbohydrates  0.7,  and  ash  4.4  per  cent.  The  average  of  20  analyses 
in  which  protein  and  carbohydrates  were  determined  by  difference  gives :  Water 
28.3,  protein  and  carbohydrates  38,  fat  32.7,  and  ash  4  per  cent.  The  average  of 
78  analyses  in  which  the  carbohydrates  and  ash  were  determined  by  difference  gives  : 
Water  24.9,  protein  38,fat  32.7,  carbohydrates  and  ash  4.4  per  cent.  The  average  of 
148  analyses  of  green  cheese  in  which  the  carbohydrates  and  ash  were  determined  by 
difference  gives :  Water  33,  protein  28.6,  fat  33.7,  carbohydrates  and  ash  4.7  per  cent. 

4  Contained  1.47  per  cent  common  salt. 

6  Contained  3.51  per  cent  common  salt. 

6  The  average  of  10  analyses  in  which  protein  and  sugar  were  not  determined 


Chemical  Composition,  American  Food  Materials  403 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


°  as 

PROTEIN 

«« 

HQ 

FOOD  MATERIALS 

1 
«g 

§ 

« 

2 

L 

« 

Jjj 

|| 

iJ 

g 

s 

X 

|i 

h 

1  S 

• 

gg 

& 

w 

m 

£ 

S3 

i 

4< 

N 

ow 

• 

ANIMAL  FOOD  —  Continued 

DAIRT    PRODUCTS,   ETC.  — 

Continued 

Cheese,  partly  skimmed 
milk,       as      pur- 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

chased :  l 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average     .... 

3 



38.2 

25.4 



29.5 

3.6 

3.3 

1785 

Cheese,     pineapple,     as 

purchased  :  2 

Average     .... 

5 



23.0 

29.9 



38.9 

2.6 

5.6 

2245 

Cheese,     Roquefort,     as 

purchased  3      .     . 

1 



39.3 

22.6 



29.5 

1.8 

6.8 

1700 

Cheese,    skimmed    milk, 

as  purchased  :  4 

Average      .... 

9 



45.7 

31.5 



16.4 

2.2 

4.2 

1320 

Cheese,    Swiss,    as    pur- 

chased :  8 

Average      .... 

2 



31.4 

27.6 



34.9 

1.3 

4.8 

2010 

Cheese,  whole  milk,.  (See 

Full  cream  cheese.) 

Cream,  as  purchased  8     . 

.  — 

:  

74.0 

2.5 



18*5 

4.5 

0.5 

910 

Koumiss,  as  purchased  :  7 

Average      .... 

8 



89.3 

2.8 



2.1 

5.4 

0.4 

240 

gives:   Water  53.6,  protein  and  sugar  (by  difference)  18.9,  fat  27.7,  lactic  acid  1.2, 
and  ash  2.6  per  cent  (including  1.4  per  cent  common  salt). 

1  Three  cheeses  were  analyzed  when  1,  3,  and  5  weeks  old.     The  average  com- 
position is  as  follows:    When  1  week  old,  water  38.4,  protein  25,  fat  30,  carbohy- 
drates 3.3,  and  ash  3.3  per  cent ;  when  3  weeks  old,  water  38.4,  protein  25.3,  fat  29, 
carbohydrates  4,  and  ash  3.3  per  cent ;   when  5  weeks  old,  water  37.7,  protein  26, 
fat  29.7,  carbohydrates  3.2,  and  ash  3.4  per  cent. 

2  Four  samples  contained  an  average  of  2.13  per  cent  common  salt. 

3  Contained  5.3  per  cent  common  salt. 

*  Two  samples  contained  an  average  of  1.5  per  cent  common  salt. 

5  Contained  1.9  per  cent  common  salt. 

8  The  averages  given  for  butter,  buttermilk,  cream,  skim  milk,  and  whole  milk  are 
assumed  from  the  most  reliable  data  available,  but  are  not  averages  of  all  analyses. 

7  Contained,  on  the  average,  4.4  per  cent  cane  sugar  and  0.76  per  cent  alcohol 
Ash  not  reported,  but  assumed  from  European  analyses. 


404 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

1  NUMBER  OF  1 
ANALYSES 

1 
tf 

WATER 

PROTEIN 

h 

TOTAL  CARBO- 
HYDRATES 

w 

• 
< 

g« 

>1 
K 

iO 
<N 

e 

x 
fc 

i. 
!' 

ANIMAL  FOOD  —  Continued 

DAIRY  PRODUCTS,    ETC.  

Continued 

Milk,  condensed,    sweet- 
ened.aspurchased:1 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Cal- 
ories 

Average     .... 

24 



26.9 

8.8 



8.3 

54.1 

1.9 

1520 

Milk,     condensed,      un- 

sweetened, "evap- 

orated cream,"  as 

purchased  : 

Average      .     .     ..    .. 

6 



68.2 

9.6 



9.3 

11.2 

1.7 

780 

Milk,  skimmed,  as  pur- 

chased 2       ... 

— 



-90S 

Q7  A 

3.4 

O    O 



0.3 
A  n 

5.1 
e  n 

0.7 

a<7  -i 

170 

OQC 

JVlilk,  whole,  as  purchased* 
Whey,  as  purchased 

— 



o«  -U 

93.0 

o.o 

1.0 



•l.U 

0.3 

•>.u 
5.0 

/   J 

0.7 

0B0 

125 

MISCELLANEOUS 

Gelatin,  as  purchased  : 

Average      .... 

6 



13.6 

91.4 

84.2 

0.1 



2.1 

1705 

Calf's-foot  jelly,  as  pur- 

chased   .... 

1 



77.6 

4.3 





17.4 

0.7 

405 

Isinglass,     sturgeon,     as 

purchased   .     .     . 

1 



19.0 

89.3 

77.4 

1.6 



2.0 

1730 

Spinal  column,  sturgeon, 

as  purchased    . 

1 



17.7 

59.8 



17.1 

0.8 

4.6 

1850 

Lard,    refined,    as    pur- 

chased   .     .     ... 

1 









100.0 





4220 

Lard,  unrefined,  as  pur- 

chased : 

Average      .... 

3 



4.8 

2.2 

1.1 

94.0 



0.1 

4010 

Tallow,  refined,  as  pur- 

chased   .... 

1 









100.0 





4220 

Cottolene,  as  purchased  . 

1 









100.0 





4220 

Oleomargarine,    as    pur- 

chased   .... 

41 



9.5 

1.2 



83.0 



6.3 

3525 

Beef  juice,  as  purchased 

1 



93.0 

4.9 



0.6 



1.5 

115 

1  Sixteen  samples  contained,  on  the  average,  43.6  per  cent  cane  sugar. 

2  The  averages  given  for  butter,  buttermilk,  cream,  skim  milk,  and  whole  milk  are 
assumed  from  the  most  reliable  data  available,  but  are  not  averages  of  all  analyses. 

3  According  to  Farrington  and  Woll  the  ash  of  cow's  milk  contains,  on  the 
average,  K2O  25.6,  NaaO  12.5,  CaO  24.6,  P2O5  21.2,  and  Cl  16.3  per  cent. 


Chemical  Composition,  American  Food  Materials  405 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


il 

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*  "*"*  _C 

W   Q 

FOOD  MATERIALS 

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VEGETABLE  FOOD 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

FLOURS,  MEAL8,    ETC. 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Barley,  granulated     .     . 

1 



10.9 

7.5 

0.9 

79.8 

0.7 

0.9 

1660 

Barley  meal  and  flour  : 
Average      .... 

3 

^L_ 

11.9 

10.5 

2.2 

72.8 

3)6.5 

2.6 

1640 

Barley,  pearled  : 
Average      .... 

3 



11.5 

8.5 

1.1 

77.8 

OO.S 

1.1 

1650 

Buckwheat  flour  : 
Average      .     .     .     . 

17 



13.6 

6.4 

1.2 

77.9 

8)0.4 

0.9 

1620 

Buckwheat  preparations  : 

Farina  and  groats  — 
Average      .... 

2 

—  — 

10.9 

4.1 

0.4 

84.1 

0.2 

0.5 

1660 

Seif-raising  — 
Average      .... 

14 

11.6 

8.2 

1.2 

73.4 

W0.4 

5.6 

1570 

Corn  flour  :  l 
Average      .... 

3 



12.6 

7.1 

1.3 

78.4 

0.9 

0.6 

1645 

Corn  meal,  granular  :  2 
Average      .... 

19 



12.5 

9.2 

1.9 

75.4 

OO/.O 

1.0 

1655 

Corn  meal,  unbolted  : 

Edible  portion  — 
Average      .... 

7 



11.6 

8.4 

4.7 

74.0 



1.3 

1730 

As  purchased  — 
Average      .... 

7 

10.9 

10.3 

7.5 

4.2 

65.9 



1.2 

1545 

Pop  corn  : 
Average      .... 

, 



4.3 

10.7 

5.0 

78.7 

1.4 

1.3 

1875 

Corn  preparations  : 

Cerealine  3  — 
Average      .... 

5 



10.3 

9.6 

1.1 

78.3 

W0.4 

0.7 

1680 

Hominy  — 
Average      .... 
Hominy,  cooked     .     . 

17 

1 



11.8 

79.3 

8.3 

2.2 

0.6 

0.2 

79.0 

17.8 

WW 

0.3 

0.5 

1650 

380 

Parched  — 

? 

5.2 

11.5 

8.4 

72.3 



2.6 

1915 

1  Average  of  77  analyses  of  corn  meal  used  for  fodder  gives  water  15  protein  82, 
fat  3  8  carbohydrates  68.7,  fiber  1.9,  and  ash  1.4  per  cent;  andfuel  value  1610  calones. 

2  The  ash  of  1  sample  contained  0.185  per  cent  phosphorus. 

3  The  ash  of  1  sample  contained  0.192  per  cent  phosphorus. 


406 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


P 

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FOOD  MATEBIALS 

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VEGETABLE  FOOD  — 

Continued 

FLOURS,  MEALS,  ETC.  

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Continued 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Kafir  corn     

1 



16.8 

6.6 

3.8 

70.6 

1.1 

2.2 

1595 

Oatmeal:1 

Average     .... 

16 



7.3 

16.1 

7.2 

67.5 

(9)0.9 

1.9 

1860 

Oatmeal,  boiled     .     .     . 

1 



84.5 

2.8 

0.5 

11.5 



0.7 

285 

Oatmeal  gruel  : 

Average      .... 

2 



91.6 

1.2 

0.4 

6.3 



0.5 

155 

Oatmeal  water  : 

Average      .... 

2 



96.0 

0.7 

0.1 

2.9 



0.3 

70 

Oats,  other  preparations  :2 

Rolled  oats  — 

Average     .... 

20 



7.7 

16.7 

7.3 

66.2 

(*)1.S 

2.1 

1850 

Miscellaneous  — 

Average     .... 

26 



7.9 

16.3 

7.3 

66.8 

(20)0.,9 

1.7 

1855 

All  analyses,  average3 

46 



7.8 

16.5 

7.3 

66.5 

(22)  1.0 

1.9 

1850 

Rice: 

•  Average     .... 

21 



12.3 

8.0 

0.3 

79.0 

(13)0.# 

0.4 

1630 

Rice,  boiled: 

Average     .     .     .     . 

3 



72.5 

2.8 

0.1 

24.4 



0.2 

510 

Rice,  flaked  : 

Average     .... 

2 



9.5 

7.9 

0.4 

81.9 

0,2 

0.3 

1685 

Rice  flour  :  * 

Average     .... 

4 



8.5 

8.6 

6.1 

68.0 

16.1 

8.8 

1680 

Rye  flour  : 

Average     .... 

8 



12.9 

6.8 

0.9 

78.7 

(4)0~4 

0.7 

1630 

Rye  meal      

1 



11.4 

13.6 

2.0 

71.5 

1.8 

1.5 

1665 

1  The  ash  of  1  sample  contained  0.414  per  cent  phosphorus. 

2  The  preparations  analyzed  include  a  considerable  number  of  brands,  each  of 
which  varies  in  composition  only  slightly  from  the  average. 

3  The  ash  of  5  samples  contained  an  average  of  0.418  per  cent  phosphorus. 

4  Rice  flour  is  used  mainly  as  a  fodder,  and  varies  considerably  in  composition. 
The  ash  of  2  samples  contained  an  average  of  P2Os  29.1,  K2O  12.6,  CaO  1,  MgO  7.6, 
and  SOs  0.3  per  cent.     Two  samples  contained  an  average  of  protein  (NX  6.25) 
11.8,  and  proteids  11.6  per  cent. 


Chemical  Composition,  American  Food  Materials  407 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


*T> 

°  3? 

8. 

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FOOD  MATERIALS 

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VEGETABLE  FOOD  — 

Continued 

FLOURS,   MEALS,   ETC.  

Continued 

Wheat   flour,   California 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Cal- 
ories 

Average      .... 

3 



13.8 

7.9 

1.4 

76.4 



0.5 

1625 

Wheat  flour.entire  wheat  : 
Average      .... 

9 



11.4 

13.8 

1.9 

71.9 

(i)0.9 

1.0 

1675 

Wheat  flour,  gluten  : 
Average      .     .     .     • 

5 

r_ 

12.0 

14.2 

1.8 

71.1 

«0.ff 

0.9 

1665 

Wheat  flour,  Graham  : 
Average     .... 

13 



11.3 

13.3 

2.2 

71.4 

0)1.9 

1.8 

1670 

Wheat    flour,    prepared 

(self-raising)  :  a 
Average      .... 

29 



10.8 

10.2 

1.2 

73.0 

(8)0.4 

4.8 

1600 

Wheat  flour,  patent  roller 

process,      bakers' 

grade  : 
Average     .... 

14 



11.9 

13.3 

1.5 

72.7 

(00.7 

0.6 

1665 

Wheat  flour,  patent  roller 

process,  family  and 

straight  grade  : 

Spring  wheat  — 
Average      .... 

3 



11.9 

10.9 

1.1 

75.6 

(00.1 

0.5 

1655 

Winter  wheat  »  — 
Average      .... 

6 



13.1 

12.3 

1.1 

73.0 

Wo.s 

0.5 

1635 

Undesignated  — 
Average      .... 
All  analyses,  average  . 

19 



12.9 
12.8 

10.4 
10.8 

1.0 
1.1 

75.2 

74.8 

Wo./ 

0.5 
0.5 

1635 
1640 

1  The  ash  of  3  complete  samples  contained  an  average  of  49^3  per  cent  PjOs. 

2  The  flours  analyzed  included  18  variet  The  variation  betweei 


the  mineral  matters  added  for  rawing.  d      Q  4Q  3 

s  Thp  ash  of  1  sample  contained  foO  36.3,  Cat)  o.7,  Mgu  o.t,  ai 
per  clnt.     In  1  sample  protein  (N  X  6.25)  11.4  and  proteids  10.8  per  cent. 


408 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


IN  -A 

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VEGETABLE  FOOD  — 

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FLOURS,   MEALS,   ETC. 

Continued 

Wheat  flour,  patent  roller 
process,  grade  not 
indicated  : 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Cal- 
ories 

Average      .... 

111 



11.5 

11.4 

1.0 

75.6 

(15)0.^ 

0.5 

1660 

Wheat  flour,  patent  roller 

process,  high  grade 

Spring  wheat  — 

Average      .... 

23 



12.3 

11.7 

1.1 

74.5 

(7)OJ 

0.4 

1650 

Winter  wheat  i  — 

Average      .... 

6 



13.3 

11.0 

0.9 

74.4 

0.3 

0.4 

1625 

Undesignated  — 

Average      .... 

28 



12.5 

10.8 

1.0 

75.2 

Woj 

0.5 

1640 

All  analyses,  average  . 

57 



12.4 

11.2 

1.0 

74.9 

(14)0.^ 

0.5 

1645 

Average  of  all  analyses 

of  high  and   me- 

dium grades  and 

grade     not     indi- 

cated      .... 

210 



12.0 

11.4 

1.0 

75.1 

(41)0.3 

0.5 

1650 

Wheat  flour,  patent  roller 

process,  low  grade2 

Average      .... 

13 



12.0 

14.0 

1.9 

71.2 

(7)O.S 

0.9 

1665 

Wheat  flour,  unclassified 

process,  grade  not 

indicated  : 

Spring  wheat  3  — 

Average      .... 

4 



12.4 

10.5 

1.0 

75.4 

(3)0.5 

0.7 

1640 

»  The  ash  of  1  sample  contained  K2O  38.5,  CaO  5.6,  MO  4.4,  P2Os  48.1,  and 
SOs  0.2  per  cent.  In  1  sample  protein  (N+  6.25)  10.6  and  proteids  10.3  per  cent. 

2  The  ash  of  1  sample  contained  IfcsO  32.3,  CaO  4.5,  MgO  9.3,  and  PaOs  53.1 
per  cent.  In  1  sample  protein  (N  X  6.25)  14.1  and  proteids  13.8  per  cent. 

*  Three  samples  contained  an  average  of  starch  70.8,  dextrin  1.5,  and  sugar,  etc., 
1.8  per  cent. 


Chemical  Composition,  American  Food  Materials  409 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


°g 

o| 

£'•$  8 
6  §5 

gg 

FOOD  MATERIALS 

si 

§ 

a 

Ej 

!1 

§|| 

£| 

I  £ 

5 

I 

1 

R 

isJ 

ilS 

H 

6 

^ 

& 

> 

£ 

h 

5 

£ 

< 

VEGETABLE  FOOD  — 

Continued 

FLOURS,   MEALS,    ETC.  — 

Continued 

Wheat  flour,  unclassified 

process,  grade  not 

indicated  :  —  Con- 

tinued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Winter wheat  1  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

31 



11.9 

10.7 

1.0 

75.8 

(5)0.4 

0.6 

1650 

Undesignated  2  — 

Average      .... 

8 



9.4 

10.4 

1.3 

78.4 

W0.9 

0.6 

1700 

All  analyses,  average  . 

33 



11.4 

10.6 

1.1 

76.3 

0.6 

1665 

Wheat         preparations, 

breakfast  foods  :  » 

Cracked  and  crushed4  — 

Average      .... 

11 



10.1 

11.1 

1.7 

75.5 

(7)1.7 

1.6 

1685 

Farina  6  — 

Average      .... 

9 



10.9 

11.0 

1.4 

76.3 

(7)0.4 

0.4 

1685 

Flaked  «  — 

Average     .... 

7 



8.7 

13.4 

1.4 

74.3 

1.8 

2.2 

1690 

Germs  6  — 

Average      .... 

10 



10.4 

10.5 

2.0 

76.0 

(8)0.5 

1.1 

1695 

Glutens  7  — 

Average      .... 

3 



8.9 

13.6 

1.7 

74.6 

1.3 

1.2 

1715 

1  Four  samples  contained  an  average  of  starch  71.9,  dextrin  2.3,  and  sugar,  etc., 

1.6  per  cent. 

2  Three  samples  contained  an  average  of  starch  71.8,  dextrin  2,  and  sugar,  etc., 

1.7  per  cent. 

3  The  different  groups  of  wheat  breakfast  foods  contain  various  brands,  which 
have  been  arranged  as  far  as  possible  according  to  similarity  in  method  of  prepara- 
tion.    The  varieties  under  each  group  differ  only  slightly  from  the  average  in  per- 
centage composition. 

«  The  ash  of  2  samples  contained  an  average  of  0.282  per  cent  of  phosphorus. 
6  The  ash  of  1  sample  contained  0.153  per  cent  of  phosphorus. 

6  The  ash  of  2  samples  contained  an  average  of  0.247  per  cent  of  phosphorus. 

7  The  ash  of  1  sample  contained  0.251  per  cent  of  phosphorus. 


410 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES  | 

| 

WATER 

2 

1 

TOTAL  CARBOHY- 
DRATES (includ- 
ing Fiber) 

FIBER  (Number  of 
Determinations 
in  Parentheses) 

j 

11 

is 

VEGETABLE  FOOD  — 

Continued 

FLOURS,    MEALS,   ETC.  — 

Continued 

Wheat         preparations, 

breakfast     foods  l 
—  Continued 
Miscellaneous*  — 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Cal- 
ories 

Average     .... 

22 



9.4 

13.1 

3.1 

74.1 

(u)0.9 

1.3 

1710 

Parched  and  toasted  3— 

Average     .... 

6 



8.6 

13.6 

3.4 

74.5 

0.8 

0.9 

1740 

Shredded  — 

Average      .... 

6 



8.1 

10.5 

1.4 

77.9 

(3)1.7 

2.1 

1700 

All  analyses,  average  . 

74 



9.6 

13.1 

1.8 

75.2 

1.0 

1.3 

1700 

Wheat  preparations  : 

Macaroni  — 

Average     .... 

11 



10.3 

13.4 

0.9 

74.1 



1.3 

1665 

Macaroni,  cooked  .     . 

1 



78.4 

3.0 

1.5 

15.8 



1.3 

415 

Noodles  — 

Average     .... 

3 



10.7 

11.7 

1.0 

75.6 

0.4 

1.0 

1665 

Spaghetti  — 

Average     .... 

3 



10.6 

13.1 

0.4 

76.3 

(*)04 

0.6 

1660 

Vermicelli  — 

Average     .... 

15 



11.0 

10.9 

2.0 

72.0 

—  — 

4.1 

1625 

BREAD,    CRACKERS, 

PASTRY,   ETC. 

Bread,    brown,    as   pur- 

chased — 

Average     .     .     .     .- 

3 



43.6 

5.4 

1.8 

47.1 



2.1 

1050 

1  The  different  groups  of  wheat  breakfast  foods  contain  various  brands,  which 
have  been  arranged  as  far  as  possible  according  to  similarity  in  method  of  prepara- 
tion. The  varieties  under  each  group  differ  only  slightly  from  the  average  in  per- 
centage composition. 

J  The  ash  of  4  samples  contained  an  average  of  0.35  per  cent  of  phosphorus. 

»  The  ash  of  1  sample  contained  0.288  per  cent  of  phosphorus. 


Chemical  Composition,  American  Food  Materials   411 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


lie 

|"U 

8  « 

FOOD  MATERIALS 

°§ 

gg 

| 

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ill 

gi 

12 
&* 

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gf* 

oQ.S 

g 

i« 

VEGETABLE  FOOD  — 

Continued 

BREAD,  CRACKERS,  PAS- 

TRY, ETC.  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Bread, cassava,   as  pur- 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

chased    .... 

1 



10.5 

9.1 

0.3 

79.0 



1.1 

1650 

Bread,  corn  (johnnycake) 

as  purchased  :  1 

Average      .... 

5 



38.9 

7.9 

4.7 

46.3 



2.2 

1205 

Bread,  rye,  as  purchased  : 

Average     .     .     .     . 

21 

35.7 

9.0 

0.6 

53.2 

(l\flK 

•|     g 

1180 

Bread,  rye,  black,  as  pur- 

. 

chased    .... 

1 



36.9 

9.6 

0.6 

48.9 



4.0 

1115 

Bread,  rye,  whole,  as  pur- 

chased — 

Average      .... 

2 



50.7 

11.9 

0.6 

35.9 

1.2 

6.9 

915 

Bread,  rye  and  wheat,  as 

purchased   .     .     . 

1 



35.3 

11.9 

0.3 

51.5 



1.0 

1190 

Bread,  wheat: 

Buns,  as  purchased 

1 



29.0 

6.3 

6.5 

57.3 

04 

0.9 

1455 

Buns,     cinnamon,     as 

purchased   .     .     . 

1 



23.6 

9.4 

7.2 

59.1 



0.7 

1575 

Buns,  currant,  as  pur- 

chased   .... 

1 



27.5 

6.7 

7.6 

57.6 

l.l 

0.6 

1515 

Buns,  hot  cross,  as  pur- 

chased   .... 

1 



36.7 

7.9 

4.8 

49.7 



0.9 

1275 

Buns,    sugar,    as   pur- 

chased'— 

Average      .... 

3 



29.6 

8.1 

6.9 

54.2 

0)0.5 

1.2 

1456 

Gluten  bread,  as  pur- 

chased — 

Average     .... 

6 



38.2 

9.3 

1.4 

49.8 

1.3 

1160 

1  Corn  bread  (johnnycake),  made  of  Indian  meal  mixed  with  sour  milk  or  butter- 
milk. 

»  One  sample  contained  sugar  7.9,  dextrin  3.2,  and  starch  47  per  cent. 


412 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


8s 

H 

§2 

III 

J2«  » 

gg 

FOOD  MATERIALS 

NUMBER 
ANALYSB 

B 

I 

9 

1 

g 

EH 

3TAL  CAR: 
CRATES  (ir 
ing  Fiber) 

:BER  (Num 
Determina 
in  Parenth 

>l 
ft 

8 

$ 

£ 

£ 

H 

fi 

< 

VEGETABLE  FOOD  — 

Continued 

BREAD,    CRACKERS,    PAS- 

TRY, me.—  Continued 

Bread,  wheat  —  Continued 
Graham  bread,  as  pur- 
chased l  — 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average     .... 

37 



35.7 

8.9 

1.8 

53.1 

(")  1.1 

1.5 

1310 

Biscuit,  homemade,  as 

purchased  2  — 

Average      .... 

3 



33.9 

8.7 

3.6 

55.3 

(2)0.7 

0.5 

1300 

Biscuit,  Maryland,  as 

purchased  3  — 

Average     .... 

3 



34.6 

8.4 

5.6 

60.1 

1.3 

1.3 

1510 

Biscuit,  soda,  as  pur- 

chased   .... 

1 



22.9 

9.3 

13.7 

52.6 



1.5 

1730 

Rolls,  French,  as  pur- 

chased 4 

Average      .... 

3 



33.0 

8.5 

3.5 

55.7 

0.6 

1.3 

1300 

Rolls,    plain    as    pur- 

chased — 

Average      .... 

5 



35.3 

9.7 

4.3 

59.9 

(2)0.3 

1.0 

1470 

Rolls,  Vienna,  as  pur- 

chased   .... 

1 



31.7 

8.5 

2.2 

56.5 

04 

1.1 

1300 

Rolls,   water,   as  pur- 

chased — 

Average      .... 

3 



33.6 

9.0 

3.0 

54.3 



1.3 

1300 

Rolls,  all  analyses,  as 

purchased   .     . 

30 



39.3 

8.9 

4.1 

56.7 

(12)0.<S 

1.1 

1395 

Rolls,  large,  cheap,  as 

purchased   .     .     . 

1 



29.4 

9.4 

0.8 

59.4 



1.0 

1315 

1  Two  samples  contained  an  average  of  sugar  3.2,  dextrin  3.1,  and  starch  40.8 
per  cent. 

2  Two  samples  contained  an  average  of  sugar  2.7,  dextrin  5.5,  and  starch  41.5 
per  cent. 

3  One  sample  contained  sugar  3.9,  dextrin  2.8,  and  starch  52.2  per  cent. 

4  One  sample  contained  sugar  2.9,  dextrin  2.8,  and  starch  48.6  per  cent. 


Chemical  Composition,  American  Food  Materials  413 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


|| 

Hi 

0 

«.s~ 

'all 

5  ° 

FOOD  MATERIALS 

£s 

^ 

0^| 

z'a  ® 

x 

Si 

w 

Pj 

3 

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11 

I 

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1 

1 

Ji.s 

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1 

IB 

VEGETABLE  FOOD  — 

Continued 

BREAD,    CRACKERS,    PAS- 

TRY, ETC.  —  Continued 

Bread,  wheat  —  Continued 
Toasted  bread,  as  pur- 
chased — 

Per 

Cent 

Per 
Cent 

Pei 

Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Cal- 
ories 

Average      .... 

5 



24.0 

11.5 

1.6 

61.2 



1.7 

1420 

White   bread,   biscuit, 

as  purchased  — 

Average      .... 

3 



35.2 

8.0 

1.4 

54.3 

(2)0.3 

1.1 

1220 

White    bread,    butter, 

as  purchased  — 

1 



32.2 

7.9 

1.1 

57.7 

0.4 

1.1 

1265 

White  bread,  cheap  grade, 

as  purchased  — 

6 

10.9 

1.3 

nr 

1.0 

1255 

White  bread,  cream,  as 

purchased  — 
Average      .... 

6 



33.2 

9.8 

0.9 

55.0 

0)0.* 

1.1 

1245 

White  bread,  homemade, 

as  purchased  — 
Average      .... 

38 



35.0 

9.1 

1.6 

53.3 

COO.* 

1.0 

1225 

White    bread,    milk,    as 

purchased  — 
Average      .... 

8 



36.5 

9.6 

1.4 

51.1 



1.4 

1190 

Wh^  hre-ad.  miscellane- 

ous, as  purchased^:  l 
Average      .     .     .     . 

103 

35.6 

9.3 

1.2 

52.7 

(8)0.5 

1.2 

1205 

White  bread,  New  Eng- 

land, as  purchased  : 
Average      .... 

7 



36.6 

9.1 

1.2 

52.1 



1.0 

1190 

White  bread,  Quaker,  as 

purchased  — 
Average      .... 

4 



35.8 

8.3 

1.1 

53.7 

(,„* 

1.1 

1200 

i  Four  samples  contained  an  average  of 
per  cent. 


sugar  2.3,  dextrin  4.2,  and  starch  48.2 


414 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


si 

°s? 

0  w 

Hi 

gg 

FOOD  MATERIALS 

«s 

fc 

O  ^X! 

2  p 

H  S 

1 

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& 

3 

<  <  bfl 

IP 

j 

I5 

& 

H 

1 

1 

Ju 

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S 

IB 

VEGETABLE  FOOD  — 

Continued 

BREAD,  CRACKERS,  PAS- 

TRY, ETC.  —  Continued 

Bread  ,  wheat  —  Continued 
White    bread,    split,    as 
purchased  — 
Average      .... 

3 

Per 
Cent 

Per 
Cent 
34.6 

Per 
Cent 
9.3 

Per 
Cent 
1.0 

Per 
Cent 
54.1 

Per 

Cent 

0)0.  # 

Per 
Cent 
1.0 

Cal- 
ories 
1330 

White  bread,  Vienna,  as 

purchased  — 

Average      .... 

35 



34.3 

9.4 

1.3 

54.1 

(9)0.5 

1.1 

1330 

White  bread,  all  analyses, 

as  purchased,  aver- 

age *  

198 



35.3 

9.3 

1.3 

53.1 

(?*)0.5 

1.1 

1315 

Whole  wheat  bread,   as 

purchased  — 

Average      .... 

12 



38.4 

9.7 

0.9 

49.7 

«*.* 

1.3 

1140 

Zwieback,  as  purchased  — 

Average      .... 

4 



5.8 

9.8 

9.9 

73.5 



1.0 

1970 

1  Analyses  of  similar  bread  made  from  different  grades  of  flour,  from  high  to  low 
grade: 


Be 

j  fc 

« 

to 

s§ 

•<  P 

1 

1 

1 

§5 

K  K 

6* 

I 

S 

S 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

White bread  from  high-grade  patent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

.flour       

32.9 

8.7 

1.4 

56.5 



0.5 

1270 

White  bread  from  regular  patent  flour 

34.1 

9.0 

1.3 

54.9 

• 

0.7 

1245 

White  bread  from  baker's  flour  . 

39.1 

10.6 

1.2 

48.3 



0.9 

1145 

White  bread  from  low-grade  flour  . 

40.7 

12.6 

1.1 

44.3 



1.3 

1105 

Chemical  Composition,  American  Food  Materials   415 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 

Continued 


8 

it 

Ji 

§8 

F-OOD  MATERIALS 

] 

r\  no 

3  "a 

H  £ 

REFUSE 

I 

£ 

1 

JS, 
|3. 

"«"-£( 

81. 

s 

|8 

VEGETABLE  FOOD  — 

Continued 

BREAD,   CRACKERS,   PAS- 

TRY, ETC.  —  Continued 

Crackers  : 

Boston  (split)  crackers, 
as  purchased  — 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Cal- 
ories 

Average      .... 

3 



7.5 

11.0 

8.5 

71.1 

0)0  8 

1.9 

1885 

Butter     crackers,     as 

purchased  : 

Average 

3 

7  2 

A  /; 

in  i 

>  |     |» 

/2\/"J    / 

i  e 

•fl  AAV 

Cream     crackers,     as 

•  MB 

«f  *O 

i".  i 

fjUfl 

()  -4 

l*o 

nw 

purchased  — 

Average     .... 

9 



6.8 

9.7 

13.1 

69.7 

(*)0.6 

1.7 

1990 

Egg  crackers,  as  pur- 

chased — 

Average     .... 

3 



5.8 

13.6 

14.0 

66.6 

0.4 

1.0 

3060 

Flatbread,      as      pur- 

chased : 

Average      .... 

3 



9.8 

14.9 

0.5 

73.6 



1.3 

1665 

Graham    crackers,    as 

purchased  — 

Average      .... 

4 



5.4 

10.0 

9.4 

73.8 

2)1.6 

1.4 

1955 

Miscellaneous,  as  pur- 

chased — 

Average     .... 

31 



7.1 

10.3 

8.8 

73.4 

")0.4 

1.5 

1905 

Oatmeal    crackers,    as 

purchased  — 

Average      .... 

3 



6.3 

11.8 

11.1 

69.0 

i)1.9 

1.8 

1970 

Oyster     crackers,     as 

purchased  — 

Average      .... 

7 



4.8 

11.3 

10.5 

70.5 

i)0.2 

3.9 

1965 

Pilot    bread,    as    pur- 

chased : 

Average     .... 

3 



8.7 

11.1 

5.0 

74.3 

)O.S 

1.0 

1800 

Pretzels,  as  purchased  : 

Average      .... 

3 



9.6 

9.7 

3.9 

73.8 

)0.5 

4.0 

700 

Saltines,  as  purchased  : 

Average      .... 

3 



5.6 

10.6 

13.7 

68.5 

0.6 

3.6 

2005 

416 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

j 

WATER 

PROTEIN 

1 

TOTAL  CARBOHY- 
DRATES (includ- 
ing Fiber) 

FIBER  (Number  of 
Determinations 
in  Parentheses) 

1 

II 

H« 

IB 

VEGETABLE  FOOD  — 

Continued 

BREAD,   CRACKERS,   PAS- 

TRY, ETC.  —  Continued 

Crackers  —  Continued 
Soda..craj5kers,  as  pur- 
chased — 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Cal- 
ories 

Average     .... 

5_ 



5.9 

9.8 

9.1 

73.1 

C)0.3 

2.1 

1925 

Water      crackers,      as 

purchased  — 

Average     .... 

6 



6.4 

11.7 

5.0 

75.7 

0.4 

1.2 

1835 

All  analyses,   as  pur- 

chased, average    . 

71 



6.8 

10.7 

8.8 

71.9 

(«)0.5 

1.8 

1905 

Cracker  meal,  as  pur- 

chased — 

Average     .... 

3 



9.2 

10.9 

6.0 

72.9 

0.2 

1.0 

1810 

Baker's  cake,  as  pur- 

chased — 

Average     .     .     .     .  ( 

2 



31.4 

6.3 

4.6 

56.9 



0.8 

1370 

Chocolate  layer  cake, 

-  ~~ 

as  purchased 

1 



20.5 

6.2 

8.1 

64.1 



1.1 

1650 

Coffee    cake,   as   pur- 

chased — 

Average     .... 

5 



21.3 

7.1 

7.5 

63.2 

0)0.4 

0.9 

1625 

Cup  cake,  as  purchased  : 

Average     .... 

2 



15.6 

5.9 

9.0 

68.5 

(1)0.5 

1.0 

1765 

Drop    cake,    as    pur- 

chased   .... 

1 



16.6 

7.6 

14.7 

60.3 

0.1 

0.8 

1885 

Frosted  cake,  as  pur- 

chased — 

Average     .... 

7 



18.2 

5.9 

9.0 

64.8 



2.1 

1695 

Fruit    cake,    as    pur- 

chased — 

Average     .... 

4 



17.3 

5.9 

10.9 

64.1 



1.8 

1760 

Gingerbread,  as  pur- 

chased — 

Average      .... 

2 



18.8 

5.8 

9.0 

63.5 

(90.0 

2.9 

1670 

Chemical  Composition,  American  Food  Materials  417 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

| 

WATER 

£ 

1 

TOTAL  CARBOHY- 
DRATES (includ- 
ing Fiber) 

FIBER  (Number  of 
Determinations 
in  Parentheses) 

S 

11 

la 

VEGETABLE  FOOD  — 

Continued 

BREAD,   CRACKERS,   PAS- 

TRY, ETC.  —  Continued 

Cake  —  Continued 

Miscellaneous,  as  pur- 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

chased — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

4 



21.9 

5.9 

10.6 

60.1 



1.5 

1675 

Sponge  cake,   as  pur- 

chased — 

Average      .... 

3 

J  

15.3 

6.3 

10.7 

65.9 



1.8 

1795 

All     analyses,     except 

fruit,       as      pur- 

chased, average    . 

27 



19.9 

6.3 

9.0 

63.3 

(7)0.4 

1.5 

1675 

Cookies,  cakes,  etc.  : 

Molasses    cookies,    as 

purchased  1  — 

Average     .... 

6 



6.2 

7.2 

8.7 

75.7 



2.2 

1910 

Miscellaneous  cookies, 

as  purchased  — 

Average      .... 

5 



10.3 

6.7 

9.6 

72.4 

1.2 

1.0 

1875 

Sugar  cookies,  as  pur- 

chased 2  — 

Average      .... 

9 



8.3 

7.0 

10.2 

73.2 

(*}!•! 

1.3 

1920 

All  analyses,   as  pur- 

chased, average    . 

20 



8.1 

7.0 

9.7 

73.7 

0.5 

1.5 

1910 

Fig  biscuits  or  bars,  as 

purchased   .     .     . 

1 



17.9 

4.6 

6.6 

69.8 

1.7 

1.1 

1660 

Ginger  snaps,  as  pur- 

chased — 

Average      .... 

7 



6.3 

6.5 

8.6 

76.0 

(5)0.7 

2.6 

1895 

Lady  fingers,  as  pur- 

chased — 

Average      .... 

3 



15.0 

8.8 

5.0 

70.6 

(*)0.* 

0.6 

1685 

1  One  sample  contained  sugar  32.4,  dextrin  3.2,  and  starch  40.6  per  cent, 
a  One  sample  contained  sugar  25.2,  dextrin  1.8,  and  starch  42.7  oer  cent. 

2E 


418 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


A-T3 

°a? 

fa 

35  p 

Jll 

H 

FOOD  MATERIALS 

B  2 

I 

• 

w 

3 

*  s 

I|| 

|| 

p<i 

| 

| 

0 

H 

H  g  jjf 

cq  O  fl 

B 

P  B 

te 

M 

^ 

£ 

h 

H 

£ 

PM 

VEGETABLE  FOOD  — 

Continued 

BREAD,   CRACKERS,   PAS- 

j 

TRY,  ETC.  —  Continued 

Cookies,     cakes,     etc.  — 

Continued 
Macaroons,    as     pur- 
chased — 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average     .... 

4 



12.3 

6.5 

15.2 

65.2 

1.1 

0.8 

1975 

Wafers,  miscellaneous, 

as  purchased  — 

Average      .... 

5 



6.6 

8.7 

8.6 

74.5 

0.4 

1.6 

1910 

Wafers,      vanilla,      as 

purchased  — 

Average     .... 

6 



6.7 

6.6 

14.0 

71.6 

(B)0.3 

1.1 

2045 

Wafers,  all  analyses,  as 

purchased,  average 

11 



6.6 

7.6 

11.6 

72.9 

(w)O.S 

1.3 

1985 

Miscellaneous     cakes, 

as  purchased  — 

Average     .... 

17 



8.2 

7.6 

9.0 

74.0 

(i6)0.3 

1.2 

1900 

Doughnuts,  as  purchased 

Average     .... 

9 



18.3 

6.7 

21.0 

53.1 

WO.? 

0.9 

2000 

Jumbles,  as  purchased  : 

Average      .... 

4 



14.3 

7.4 

13.5 

63.7 

(«)0.5 

1.1 

1890 

Pie,  apple,  as  purchased  : 

Average      .... 

4 



42.5 

3.1 

9.8 

42.8 



1.8 

1270 

Pie,  cream,  as  purchased  : 

Average      .... 

3 



32.0 

4.4 

11.4 

51.2 



1.0 

1515 

Pie,  custard,  as  purchased  : 

1 



62.4 

4.2 

6.3 

26.1 



1.0 

830 

Pie,  lemon,  as  purchased  : 

1 



47.4 

3.6 

10.1 

37.4 



1.5 

1190 

Pie,  mince,  as  purchased  : 

Average      .... 

3 



41.3 

5.8 

12.3 

38.1 



2.5 

1335 

Pie,  raisin,  as  purchased  : 

1 



37.0 

3.0 

11.3 

47.2 



1.5 

1410 

Pie,  squash,  as  purchased  • 

1 



64.2 

4.4 

8.4 

21.7 



1.3 

840 

Pudding,    Indian    meal, 

as  purchased    . 

1 



60.7 

5.5 

4.8 

27.5 



1.5 

815 

Pudding,  rice  custard,  as 

purchased    . 

1 



59.4 

4.0 

4.6 

31.4 



0.6 

825 

Chemical  Composition,  American  Food  Materials  419 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


|| 

||| 

FOOD  MATERIALS 

11 

g 

S 

g 

3f| 

||| 

y 

S  7, 

fc 

g 

o 

H 

H  *  a 

«Qfl 

H  ~ 

<• 

£}  W.i-i 

fc 

tf 

^ 

£ 

fr 

E"1 

fi 

<< 

fa  * 

VEGETABLE  FOOD  — 

Continued 

BREAD,  CRACKERS,  PAS- 

TRY, ETC.  —  Continued 

* 

Pudding,  tapioca,  as  pur- 
chased— 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Cal- 
ories 

Average     .... 

3 



64.5 

3.3 

3.3 

38.3 

• 

0.8 

730 

Pudding,    tapioca,    with 

apples,     as     pur- 

chased   .... 

1 



70.1 

0.3 

0.1 

29.3 



0.2 

575 

SUGARS,  STARCHES,  ETC. 

Candy,   as  purchased  :  l 

— 









96.0 





1785 

1  AVERAGE  COMPOSITION  OF  SOME  COMMON  CANDIES 


0  g 

I! 

1 

0 

JVERT 
lUGAR 

a 
• 

INSOLUBLE  IN 
COLD  WATER 

REMARKS 

£ 

^ 

CQ 

hH 

^ 

£o 

t,  ^ 

S  01 

PnO 

fc| 

£0 

Per  Cent 

Broken  candy 

8 

4.6 

75.3 

14.0 

2.7 

0.9  in  one  sample. 

Cream  candy  . 

20 

5.3 

77.1 

8.7 

0.1 

0.2  in  one  sample. 

Marshmallows     . 

3 

5.6 

33.3 

24.1 

1.1 

27.0 

One  sample  con- 

tained 44.8  per 

cent  insoluble 

matter  (starch 

and  flour). 

Caramels    .     .     . 

3 

3.3 

37.5 

15.2 

1.4 

32.2 

One  sample  con- 

tained 66.  3  per 

cent  insoluble 

matter  (starch 

and  flour). 

Chocolate  creams 

1 

3.8 

58.3 

13.8 

0.5 

15.4 

420 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


i   t 

«*-"     ^ 

!«T3 

W  3 

°  §  1 

fo 

013 

J2  '-3JS 

FOOD  MATERIALS 

02  £ 

fcr 

*xl 

||| 

£3  * 

B 

1 

« 

w 

j  E«£ 

'"-'  fepj 

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3  * 

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H« 

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n 

^ 

AH 

fe 

H 

£ 

fe  * 

VEGETABLE  FOOD  — 

Continued 

SUGARS,  STARCHES,  ETC.  — 

B 

Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Honey, as  purchased  :  1 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average     .... 

17 



18.2 

0.4 



81.2 



0.2 

1520 

Molasses,  cane,  as  pur- 

chased : 

Average      .... 

15 



25.1 

2.4 



69.3 



3.2 

1290 

Starch,     arrowroofT    as 

purchased   . 

1 



2.3 





97.5 



0.2 

1815 

Starch,     cornstarch,     as 

purchased   .     .     . 

— 









90.0 





1675 

Starch,  manioca,  as  pur- 

chased    .... 

1 



10.5 

0.5 

0.1 

88.8 



0.1 

1665 

Starch,     sago,     as    pur- 

chased   .... 

1 



12.2 

9.0 

0.4 

78.1 



0.3 

1635 

Starch,  tapioca,  as  pur- 

chased : 

Average      .... 

7 



11.4 

0.4 

0.1 

88.0 

(5)0.1 

0.1 

1650 

Sugar,    coffee   or   brown 

sugar,     as     pur- 

chased   .... 
Sugar,  granulated  sugftr, 

328 









95.0 





1765 

as  purchased   . 

— 







100.0 





1860 

Sugar,    maple,    as    pur- 

chased : 

Average      .... 

17 









82.8 





1540 

Sugar,  powdered,  as  pur- 

chased   .... 

— 









100.0 





1860 

Syrup,    maple,    as    pur- 

chased : 

Average      .... 

50 









71.4 





1330 

1  Contained  an  average  of  cane  sugar  2.8  and  reducing  sugar  71.1  per  cent.  The 
reducing  sugar  was  composed  of  about  equal  amounts  of  glucose  (dextrose)  and 
fruit  sugar  (levulose). 


Chemical  Composition,  American  Food  Materials   421 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


P 

si! 

FOOD^MATEBIALS 

\\ 

g 

% 

3  osrS 
5  c  c 
^'g  o> 

VALUE 
POUND 

«  < 
5  £ 

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H 

B 

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H  « 

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2 

5 

£  o.S 

2  U.2 

H 

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^ 

£ 

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14 

^ 

VEGETABLE  FOOD  — 

Continued 

VEGETABLES1 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Artichokes, as  purchased  :2 
Average      .... 

2 

Cent 

Cent 
79.5 

Cent 
2.6 

Cent 
0.2 

Cent 
16.7 

Cent 
0.8 

Cent 
1.0 

ories 
365 

Asparagus,  fresh,  as  pur- 

chased :  s 

Average      .... 

3 



94.0 

1.8 

0.2 

3.3 

0.8 

0.7 

105 

Asparagus,     cooked,     as 
purchased   .     .     . 

1 



91.6 

2.1 

3.3 

2.2 



0.8 

220 

Beans,  butter,  green: 
Edible  portion    .     .     . 
As  purchased      .     .     . 

1 
1 

50.0 

58.9 
29.4 

9.4 
4.7 

0.6 
0.3 

29.1 
14.6 



2.0 
1.0 

740 
370 

Beans,    dried,     as    pur- 

chased : 
Average      .... 

11 



12.6 

22.5 

1.8 

59.6 

W4.4 

3.5 

1605 

Beans,  frijoles  (New  Mex 

ico)  ,  as  purchased 
Average      .... 

4 

7.5 

21.9 

1.3 

65.1 



4.2 

1675 

Beans,    lima,    dried,   as 

purchased  : 
Average      .... 

4 



10.4 

18.1 

1.5 

65.9 



4.1 

1625 

Beans,  lima,  fresh  :  « 
Edible  portion   .     .     . 
As  purchased     .     .     . 

1 

55.0 

68.5 
30.8 

7.1 
3.2 

0.7 
0.3 

22.0 
9.9 

1.7 
0.8 

1.7 
0.8 

570 
255 

Beans,  mesquite,  dry,  as 
purchased   .     .     . 

1 



4.8 

12.2 

2.5 

77.1 



3.4 

1765 

1  Such  vegetables  as  potatoes,  squash,  beets,  etc.,  have  a  certain  amount  of  in- 
edible material,  skin,  seeds,  etc.     The  amount  varies  with  the  method  of  preparing 
the  vegetables,  and  cannot  be  accurately  estimated.     The  figures  given  for  refuse 
of  vegetables,  fruits,  etc.,  are  assumed  to  represent  approximately  the  amount  of 
refuse  in  these  foods  as  ordinarily  prepared.  . 

2  In  1  sample,  protein  (NX6.25)   2.2  and  proteids  1.2  per  cent  contained  an 
average  orotein  (NX 6.25)  1.83  and  proteids  0.94  per  cent. 

'"TWO  samples  contained  an  average  of  0.23  per  cent  free  acid.     Three  samples 
contained  an  average  protein  (N  X  6.25)  1.83  and  proteids  0.94  per  cent. 
«  Contained  protein  (NX6.25)  7.1  and  proteids  5.7  per  cent. 


422 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


.   , 

"3  *><-, 

£  3 

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O  "5 

£'•3  $ 

FOOD  MATERIALS 

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£ 

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VEGETABLE  FOOD  — 

Continued 

VEGETABLES  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Beans,    string,     cooked, 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

edible  portion 

1 



95.3 

0.8 

1.1 

1.9 



0.9 

95 

Beans,  string,  fresh  :  l 
Edible  portion  — 

Average                .     ._ 

5 



89.2 

2.3 

0.3 

7.4 

(2)1.5 

0.8 

195 

As  purchased 

— 

7.0 

83.0 

2.1 

0.3 

6.9 

1.8 

0.7 

180 

Beets,  cooked,  edible  por- 

tion     

1 



88.6 

2.3 

0.1 

7.4 



1.6 

185 

Beets,  fresh  :  2 

Edible  portion  — 

Average      .... 

24 



87.5 

1.6 

0.1 

9.7 

(«)0.9 

1.1 

215 

A  a  TMirpV»««apr1 

20  0 

70  0 

1  3 

0  1 

7  7 

0  9 

170 

Cabbage  :  3 

Edible  portion  — 

Average     .... 

16 



91.5 

1.6 

0.3 

5.6 

(tyl.l 

1.0 

145 

As  purchased      .     . 

— 

15.0 

77.7 

1.4 

0.2 

4.8 



0.9 

125 

Cabbage,  curly,  as  pur- 

chased   .... 

1 



87.3 

4.1 

0.6 

6.2 



1.8 

215 

Cabbage  sprouts  : 

Edible  portion    .     . 

1 



88.2 

4.7 

1.1 

4.3 



1.7 

215 

As  purchased      .     .     . 

1 

61.8 

33.7 

1.8 

0.4 

1.7 



0.6 

80 

Carrots,  fresh  :  * 

Edible  portion  — 

Average      .... 

18 



88.2 

1.1 

0.4 

9.3 

(15)1.1 

1.0 

210 

As  purchased 

— 

20.0 

70.6 

0.9 

0.2 

7.4 



0.9 

160 

1  One  sample  contained  free  acid  0.49,  protein  (N  X  6.25)1.7,  and  proteids  0.87 
per  cent. 

2  The  ash  of  8  samples  contained  an  average  of  CaO  6.2,  IfcsO  44,  MgO  3.1, 
PzOs  9.4,  NazO  10.3,  and  FezOs  0.3  per  cent.     Seven  samples  contained  an  average 
of  protein  (NX6.25)  1.6,  and  proteids  0.55  per  cent. 

»  The  ash  of  2  samples  contained  an  average  of  CaO  4.7,  MgO  1.9,  P2Os  5.5, 
NaaO  6.3,  and  KzO  61.5  per  cent.  Five  samples  contained  an  average  of  protein 
(NX 6.25)  2.4  and  proteids  1.4  per  cent. 

4  The  ash  of  1  sample  contained  CaO  7.3,  foO  53.7,  MgO  2.8,  PzOs  9.8,  NazO  1.4, 


Chemical  Composition,  American  Food  Materials  423 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


si 

S81 

«"a 

:'~S  * 

H 

0 

s^'S1 

!•!  a 

5  fc 

FOOD  MATERIALS 

«« 

hi 

o  *pS 

Z  S  * 

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II 

REFUSE 

WATER 

PROTEII 

1 

H 

4 

1 

„ 

£S 

VEGETABLE  FOOD— 

Continued 

VEGETABLES  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Carrots,   cooked,    edible 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

portion  .... 

1 

3.5 

7.7 

3.6 

80.3 



4.9 

1790 

Cauliflower,       as      pur- 

chased :  l 

Average     .... 

2 



92.3 

1.8 

0.5 

4.7 

(*)1.0 

0.7 

140 

Celery  : 

Edible  portion  — 

94.5 

1.1 

0.1 

3.3 

1.0 

85 

Average      .... 
As  purchased      .     .     . 

20.0 

75.6 

0.9 

0.1 

2.6 



0.8 

70 

Collards  :  » 

Edible  portion  — 
Average      .... 
As  purchased      .     . 

2 

1 

55.3 

87.1 

39.5 

4.5 

1.5 

0.6 

0.2 

6.3 

2.9 



1.5 

0.6 

225 

90 

Corn,  green  :  3 

Edible  portion  — 
Average      .    '.     .     . 
As  purchased      .     . 

3 

61.0 

75.4 

29.4 

3.1 

1.2 

1.1 

0.4 

19.7 

7.7 

w.* 

0.7 

0.3 

470 

180 

Cucumbers  :  4 

Edible  portion  — 
Average      .... 
As  purchased      .     .     . 
Eggplant,  edible  portion  5 

4 
1 

15.0 

95.4 

81.1 
92.9 

0.8 

0.7 
1.2 

0.2 

0.2 
0.3 

3.1 

2.6 
5.1 

0.8 

0.5 

0.4 
0.5 

80 

70 
130 

Greens,  beet,  cooked,  as 
purchased   .     .     . 

1 



89.5 

2.2 

3.4 

3.2 



1.7 

245 

and  FezOz  0.8  per  cent.     One  sample  contained  protein  (N  X  6.25)  1  and  proteids 

0  5  per  cent.     One  sample  contained  cane  sugar  3.6  and  fruit  sugar  3  per  cent. 

i  One  sample  contained  free  acid  0.6,  protein  (N  X  6.25)  1.6,  and  proteids  1  per 

^bne  sample  contained  protein  (N  X  6.25)  5.7  and  proteids  2.9  per  cent. 

«  One  sample  contained  free  acid  0.01,  protein  (N  X  6.25)  2.8,  and  proteids  2.2 


ne  sample  contained  0.02  per  cent  free  acid.     Two  samples  contained  an 
average  of  protein  (N  X  6.25),  0.8,  and  proteids  0.4  per  cent. 

B  Contained  free  acid  0.01,  protein  (N  X  6.25)  1.2,  and  proteids  0.6  per  cent. 


424 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


Si 

§1 

!§? 

FOOD  MATERIALS 

PH     ® 

g 

^^D   " 

Ill 
s§£ 

11 

«     ^ 

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fa 

VEGETABLE  FOOD— 

Continued 

VEGETABLES  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Greens,    dandelion,     as 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

purchased   . 

1 



81.4 

2.4 

1.0 

10.6 



4.6 

285 

Greens,  turnip-salad,  as 

purchased  : 

Average      .... 

2 



86.7 

4.2 

0.6 

6.3 



2.2 

220 

Kohl-rabi,     edible     por- 

tion :  ! 

Average     .... 

3 



91.1 

2.0 

0.1 

5.5 

1.3 

1.3 

145 

Leeks  : 

Edible  portion   .     .     . 

1 



91.8 

1.2 

0.5 

5.8 



0.7 

150 

As  purchased      .     . 

1 

15.0 

78.Q 

1.0 

0.4 

5.0 

0.6 

0.6 

130 

Lentils,    dried,    as    pur- 

chased : 

Average     .... 

3 



8.4 

25.7 

1.0 

59.2 



5.7 

1620 

Lettuce  :  2 

~~ 

""" 

Edible  portion  — 

Average     .... 

8 



94.7 

1.2 

0.3 

2.9 

(7)0.7 

0.9 

90 

As  purchased      .     .     . 

— 

15.0 

80.5 

1.0 

0.2 

2.5 



0.8 

75 

Mushrooms,      as      pur- 

chased :  3 

Average      .... 

11 



88.1 

3.5 

0.4 

6.8 

(8)0.5 

1.2 

210 

Okra: 

Edible  portion  — 

Average      .... 

3 



90.2 

1.6 

0.2 

7.4 

0)3.4 

0.6 

175 

As  purchased      .     .     . 

— 

12.5 

78.9 

1.4 

0.2 

6.5 



0.5 

155 

1  Two  samples  contained  an  average  of  protein  (N  X  6.25)  2  and  proteids  O.i 
per  cent. 

2  The  ash  of  2  samples  contained  an  average  of  CaO5.1,  K2O  46.6,  MgO  0.8 
PzOs  5.3,  and  Na2O  3.3  per  cent.     Five  samples  contained  an  average  of  proteir 
(N  X  6.25)1.4  and  proteins  0.8  per  cent. 

3  Eight  samples  contained  an  average  of  3.1  protein  (N  X  6.25)  and  2.2  per  cenl 
proteids. 


Chemical  Composition,  American  Food  Materials  425 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


|       1 

£•§ 

2  §"g 

§« 

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FOOD  MATERIALS 

0  a 
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fa 

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VEGETABLE  FOOD  — 

Continued 

VEGETABLES  —  Continued 

Onions,  fresh  :  l 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

15 



87.6 

1  6 

0.3 

9.9 

p)nx 

O.G 

22£ 

As  purchased      .     .     . 

78.9 

1.4 

0.3" 

8.9 

0.5 

205 

Onions,  cooked,  prepared 

as  purchased    . 

1 



91.2 

1.2 

1.8 

4.9 



0.9 

190 

Onions,  green,  (New  Mex- 

ico) : 

Edible  portion  — 

Average      .... 

2 



87.1 

1.0 

0.1 

11.2 



0.6 

230 

As  purchased      .     .     . 

— 

51.0 

42.6 

0.5 

0.1 

5.5 



0.3 

115 

Parsnips  :  2 

Edible  portion  — 

* 

Average      .... 

3 



83.0 

1.6 

0.5 

13.5 

(l)2.6 

1.4 

300 

As  purchased      .     .     . 

— 

20.0 

66.4 

1.3 

0.4 

10.8 



1.1 

240 

Peas,  dried,  as  purchased  : 

Average      .... 

8 



9.5 

24.6 

1.0 

62.0 

(2)4-5 

2.9 

1655 

Peas,  green  :  3 

Edible  portion  — 

Average      .... 

5 



74.6 

7.0 

0.5 

16.9 

(l)1.7 

1.0 

465 

As  purchased      .     .     . 

— 

45.0  4 

40.8 

3.6 

0.2 

9.8 



0.6 

255 

Peas,  green,   cooked,  as 

purchased    .     .     . 

1 



73.8 

6.7 

3.4 

14.6 



1.5. 

540 

Peas,  sugar,  green,  edible 

portion  .... 

1 



81.8 

3.4 

0.4 

13.7 

1.6 

0.7 

335 

1  The  ash  of  1  sample  contained  CaO  6.4,  K2O  30.2,  MgO  2.9,  and  P2Os  12.4  per 
cent.     Four  samples  contained  an  average  of  protein  (N  X  6.25)  1.3  and  proteids 
0.6  per  cent. 

2  One  sample  contained  CaO  6,  K2O  42.2,  MgO  3.1,  P2Ot  12.8,  Na2O  0.4,  and 
Fe2Os  0.3  per  cent. 

3  One  sample  contained  protein  (N  X  6.25)  4.4,  and  proteids  4.3  per  cent. 
*  Refuse,  pods. 


426 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


AT. 

2§? 

W  3 

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n  a 

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FOOD  MATEBIALS 

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VEGETABLE  FOOD  — 

Continued 

VEGETABLES  —  Continued 

Cowpeas,  dried,  .as  pur- 
chased : 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average     .... 

13 



13.0 

21.4 

1.4 

60.8 

4.1 

3.4 

1590 

Cowpeas,    green,    edible 

portion  .... 

1 



65.9 

9.4 

0.6 

22.7 



1.4 

620 

Potatoes,  raw  or  fresh  ;  l 

j 

Edible  portion  — 

Average     .    •.     .     . 

136 

—  — 

78.3 

2.2 

0.1 

18.4 

(53)0.4 

1.0 

385 

As  purchased     .     . 

— 

20.0 

62.6 

1.8 

0.1 

14.7 



0.8 

310 

Potatoes,  evaporated,  as 

purchased  : 

Average     .     .     .     . 

3 



7.1 

8.5 

0.4 

80.9 



3.1 

1680 

Potatoes,  cooked,  boiled, 

as  purchased  :  2 

Average     .... 

11 



75.5 

2.5 

0.1 

20.9 

(W 

1.0 

440 

Potatoes,  cooked,  chips, 

. 

as  purchased  : 

Average      .... 

2 



2.2 

6.8 

39.8 

46.7 



4.5 

2675 

^Potatoes,  cooked,  mashed, 
and    creamed,    as 

purchased  : 

Average     .... 

4 



75.1 

2.6 

3.0 

17.8 



1.5 

505 

Potatoes,  sweet,  raw,  or 

fresh  :  • 

Edible  portion  — 

Average     .... 

95 



69.0 

1.8 

0.7 

27.4 

(<»)/.  3 

1.1 

570 

As  purchased 

— 

20.0 

55.2 

1.4 

0.6 

21.9 



0.9 

460 

1  One  sample  contained  0.02  per  cent  free  acid.     In  4  samples  the  average  amount 
of  proteid  nitrogen  was  57  per  cent  of  the  total  nitrogen.    Twenty  samples  contained 
an  average  of  0.8  per  cent  malic  acid,  pectose  substances,  etc.     The  ash  of  40  samples 
contained  an  average  of  CaO  1,  KzO  59.2,  MgO  4.5,  P2Os  13.8,  Na2O  4,  and  SOs  6.5 
per  cent. 

2  One  sample  contained  cane  sugar  0.2,  glucose  0.2,  and  starch  17.4  per  cent. 

»  The  edible  portion  of  26  samples  contained  an  average  of  cane  sugar  2.5  and 


Chemical  Composition,  American  Food  Materials   427 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


i-T-J 

og-sr 

w_2 

**  o  ^ 

J-)'S    V 

n  t» 

«  £!  -*•-* 

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VEGETABLE  FOOD  — 

Continued 

VEGETABLES  —  Continued 

Potatoes,  sweet,  cooked, 
and  prepared,   as 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

purchased   .     .     . 

1 



51.9 

3.0 

2.1 

42.1 



0.9 

925 

Pumpkins: 

Edible  portion  — 

Average      .... 

3 



93.1 

1.0 

0.1 

5.2 

1.2 

0.6 

120 

As  purchased 

— 

50.0 

46.5 

0.5 

0.1 

2.6 



0.3 

60 

Radishes  : 

Edible  portion  — 

Average      .... 

4 



91.8 

1.3 

0.1 

5.8 

(2)0.7 

1.0 

135 

As  purchased      . 

— 

30.0 

64.3 

0.9 

0.1 

4.0 



0.7 

95 

Rhubarb  :  l 

Edible  portion  — 

Average      .... 

2 



94.4 

0.6 

0.7 

3.6 

(l)l.l 

0.7 

105 

As  purchased      .     .  f  . 

— 

40.0 

56.6 

0.4 

0.4 

2.2 



0.4 

65 

Ruta-bagas  :  2 

Edible  portion  — 

Average      .... 

5 



88.9 

1.3 

0.2 

8.5 

1.2 

1.1 

190 

As  purchased      .     . 

— 

30.0 

62.2 

0.9 

0.1 

6.0 



0.8 

135 

Sauerkraut,  as  purchased  : 

Average      .... 

2 



88.8 

1.7 

0.5 

3.8 

,  

5.2 

125 

Spinach,    fresh,    as   pur- 

chased :  3 

Average      .... 

3 

—  — 

92.3 

2.1 

0.3 

3.2 

0.9 

2.1 

lit 

Spinach,  cooked,  as  pur- 

chased   .... 

1 



89.8 

2.1 

4.1 

2.6 



1.4 

260 

'invert  sugar  3.4  per  cent.     Two  samples  contained,  in  the  edible  portion,  an  aver- 
age of  protein  (N  X  6.25)  1.8  and  proteids  1.3  per  cent. 

1  The  edible  portion  of   1  sample   contained  free  acid  0.5,  protein  (N  X  6.25) 
0.7,  and  proteids  0.4  per  cent. 

2  The  ash  of  the  edible  portion  of  3  samples  contained  an  average  of  CaO  9.4, 
K2Q  43.6,  MgO  2.8,  P2O5  11.7,  Na2O  10.2,  and  FezOa  0.5  per  cent.     One  sample 
contained  protein  (N  X  6.25)  2  and  proteids  0.9  per  cent. 

a  The  ash  of  2  samples  contained  an  average  of  CaO  2  6,  K2O  39.9,  MgO  2.2 


428 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


^ 

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g. 

K  3 

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FOOD  MATERIALS 

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VEGETABLE  FOOD  — 

Continued 

VEGETABLES  —  Continued 

Squash  :  * 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

10 



88.3 

1.4 

0.5 

9.0 

(5)0.5 

0.8 

215 

As  purchased      .     .     . 

50.0 

44.2 

0.7 

0.2 

4.5 

0.4 

105 

Tomatoes,  fresh,  as  pur- 

chased :  2 

Average      .... 

27 



94.3 

0.9 

0.4 

3.9 

(22)0.tf 

0.5 

105 

Tomatoes,  dried,  as  pur- 

chased   .... 

1 



7.3 

12.9 

8.1 

62.3 



9.4 

1740 

Turnips  :  3 

Edible  portion  — 

Average      .... 

19 



89.6 

1.3 

0.2 

8.1 

(9)/.  3 

0.8 

185 

As  purchased      .     .     . 

— 

30.0 

62.7 

0.9 

0.1 

5.7 

0.6 

125 

VEGETABLES,    CANNED 

Artichokes,  as  purchased  : 

Average      .... 

3 



92.5 

0.8 



5.0 

o.e 

1.7 

110 

Asparagus,  as  purchased  : 

Average      .... 

14 



94.4 

1.5 

0.1 

2.8 

0.5 

1.2 

85 

Beans,    baked,    as    pur- 

chased : 

Average      .... 

21 



68.9 

6.9 

2.5 

19.6 

(12)2.5 

2.1 

600 

P2<D5  2.2,  and  NasO  9.4  per  cent.     One  sample  contained  0.01  per  cent  free  acid. 
One  sample  contained  protein  (NX6.25)  2.1  and  proteids  1.3  per  cent. 

1  The  edible  portion  of  2  samples  contained  an  average  of  protein  (N  X  6.25) 
0.6  and  proteids  0.5  per  cent. 

2  The  ash  of  1  sample  contained  CaO  5.8,  I&O  68.1,  MgO  3.7,  and  P2Os,  8.7  per 
cent.     Six  samples  contained  an  average  of  protein  (N  X  6.25)  0.8  and  proteids 
0.5  per  cent. 

3  The  ash  of  the  edible  portion  of  4  samples  contained  an  average  of  CaO  8.8, 
KaO  43,  MgO  2.7,  PzOs  11.4,  and  NaaO  8.3  per  cent.     One  sample  contained  protein 
(N  X  6.25)  0.8  and  proteids  0.2  per  cent.     One  sample  contained  4.4  per  cent 
sugar. 


Chemical  Composition,  American  Food  Materials  429 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


64 

2S? 

b 

0  a 

0-3        *-s  S 
S-9~  Sg- 

gg 

FOOD  MATERIALS 

a  £ 

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VEGETABLE  FOOD  — 

Continued 

VEGETABLES,    CANNED  

Continued 

Beans,    string,    as    pur- 
chased : 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average      .... 

29 



93.7 

1.1 

0.1 

3.8 

(18)0.5 

1.3 

95 

Beans,    little    green,    as 

purchased   .     .     . 

1 



93.8 

1.2 

0.1 

3.4 

0.6 

1.5 

90 

Beans,  wax,  as  purchased 

1 



94.6 

1.0 

0.1 

3.1 

0.6 

1.2 

80 

Beans,  haricots  verts,  as 

purchased  : 

Average      .... 

7 



95.2 

IJL 

0.1 

2.5 

0.5 

1.1 

70 

Beans,  haricots  flageolets, 

as  purchased  : 

Average      .... 

3 



81.6 

4.6 

0.1 

12.5 

1.0 

1.2 

320 

Beans,  haricots  panaches, 

as  purchased    . 

1 



86.1 

3.7 



9.2 

1.0 

1.0 

240 

Beans,     Lima,    as    pur- 

chased : 

Average      .... 

16 



79.5 

4.0 

0.3 

14.6 

(«)*•* 

1.6 

360 

Beans,    red    kidney,    as 

purchased  l      .     . 

1 



72.7 

7.0 

0.2 

18.5 

1.2 

1.6 

480 

Brussels  sprouts,  as  pur- 

chased   .... 

1 



93.7 

1.5 

0.1 

3.4 

0.5 

1.3 

95 

Corn,     green,     as     pur- 

chased :  2 

Average      .... 

52 



76.1 

2.8 

1.2 

19.0 

(*3)0.8 

0.9 

455 

Corn  and   tomatoes,   as 

purchased  : 

Average      .... 

2 



87.6 

1.6 

0.4 

9.6 

0.5 

0.8 

225 

Macedoine  (mixed  vege- 

tables) ,     as    pur- 

chased : 

Average      .... 

5 



93.1 

1.4 



4.5 

0.6 

1.0 

110 

1  Shelled. 

2  Thirty-two  samples  contained  an  average  of  0.4  per  cent  NaCl. 


430 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS 

Continued 


11 

||| 

h 
O  to 

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FOOD  MATERIALS 

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g 

O  f»J2 

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1 

1 

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1 

^ 

VEGETABLE  FOOD  — 

Continued 

VEGETABLES,  CANNED  

Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Okra, as  purchased  :  l 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

4 



94.4 

0.7 

0.1 

3.6 

0.7 

1.3 

85 

Okra    and   tomatoes,    as 

purchased  :  2 

Average      .... 

3 



91.8 

1.1 

0.3 

5.3 

0.5 

1.6 

130 

Peas,     green,     as     pur- 

chased :  3 

Average      .... 

88 



85.3 

3.6 

0.3 

9.8 

(8S)1.2 

1.1 

355 

Potatoes,  sweet,  as  pur- 

chased : 

Average      .... 

3 



55.3 

1.9 

0.4 

41.4 

(i)0.& 

1.1 

830 

Pumpkins,  as  purchased  : 

Average      .... 

7 



91.6 

0.8 

0.3 

6.7 

(5)1.1 

0.7 

150 

Squash,  as  purchased  : 

Average      .... 

5 



87.6 

0.9 

0.5 

10.5 

(2)0.7 

0.5 

335 

Succotash,  as  purchased  : 

Average      .... 

13 



75.9 

3.6 

1.0 

18.6 

(io)0.5 

0.9 

455 

Tomatoes,  as  purchased  :  4 

Average      .... 

19 



94.0 

1.3 

0.3 

4.0 

(")0.5 

0.6 

105 

PICKLES,  CONDIMENTS, 

ETC. 

Catsup,  tomato,  as  pur- 

chased : 

Average      .... 

3 



83.8 

1.5 

0.3 

13.3 



3.3 

365 

Horse-radish,      as     pur- 

chased : 

Average      .... 

3 



86.4 

1.4 

0.3 

10.5 



1.5 

330 

Horse-radish,  evaporated, 

as  purchased    .     . 

1 



4.3 

11.0 

0.8 

77.7 



6.2 

1685 

1  Three  samples  contained  an  average  of  1.1  per  cent  NaCl. 

2  Three  samples  contained  an  average  of  1  pec  cent  NaCl. 

3  Eighty  samples  contained  an  average  of  0.7  per  cent  NaCl. 

4  Seven  samples  contained  an  average  of  0.1  per  cent  NaCl. 


Chemical  Composition,  American  Food  Materials  431 


CHEMICAL  COMPOSITION  OP  AMERICAN  FOOD  MATERIALS  — 
Continued 


h 

SI 

grt 

|H 

0  8 

•o-^ 

S  §-g 

&  o 

FOOD  MATERIALS 

w 

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£'s  £ 

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VEGETABLE~TOOD  — 

Continued 

PICKLES,   CONDIMENTS, 

ETC.  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Olives, green  : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Edible  portion    .     .     . 

1 



58.0 

1.1 

27.6 

11.6 



1.7 

1400 

As  purchased 

1 

27.0 

42.3 

0.8 

20.2 

8.5 



1.2 

1025 

Olives,  ripe  : 

Edible  portion    . 
As  purchased 

1 

19.0 

64,7 

1.7 
1.4 

25.9 

21.0 

4.3 

3.5 



3.4 

2.7 

1205 

975 

Peppers  (paprika),  green, 
dried,  as  purchased 

1 

5.0 

15.5 

8.5 

63.0 

8.0 

1820 

Peppers,  red  chili,  as  pur- 

chased :  1 

Average      .... 

5 



5.3 

9.4 

7.7 

70.0 



7.6 

1800 

Pickles,     cucumber,     as 

purchased  : 

Average      .... 

3 



92.9 

0.5 

0.3 

2.7 



3.6 

70 

Pickles,    mixed,   as   pur- 

chased    .     . 

1 



93.8 

1.1 

0.4 

4.0 



0.7 

110 

Pickles,   spiced,   as  pur- 

chased    .... 

1 



77.1 

0.4 

0.1 

20.7 



1.7 

395 

FRUITS,  BERRIES,  ETC., 

FRESH  2 

Apples  :  3 

Edible  portion  — 

Average      .... 

29 



84.6 

0.4 

0.5 

14.2 

(7)  1  -^ 

0.3 

290 

As  purchased 

— 

25.0 

63.3 

0.3 

0.3 

10.8 



0.3 

220 

1  Refuse,  seeds  and  stem.  , 

z  Fruits  contain  a  certain  proportion  of  inedible  materials,  as  skin,  seeds,  etc., 
which  are  properly  classed  as  refuse.  In  some  fruits,  as  oranges  and  prunes,  the 
amount  rejected  in  eating  is  practically  the  same  as  the  refuse.  In  others,  as  apples 
and  pears,  more  or  less  of  the  edible  material  is  ordinarily  rejected  with  the  skin 
and  seeds  and  other  inedible  portions.  The  edible  material  which  is  thus  thrown 
away,  and  should  properly  be  classed  with  the  waste,  is  here  classed  with  the  refuse. 
The  figures  for  refuse  here  given  represent,  as  nearly  as  can  be  ascertained,  the 
quantities  ordinarily  rejected. 

3  The  edible  portion  of  1  sample  contained  glucose  6.4,  cane  sugar  6,  and  starch 


432 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


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VEGETABLE  FOOD  — 

Continued 

FRUITS,   BERRIES,   ETC.,- 

FRESH  —  Continued 

Apricots:  l 
Edible  portion  — 

Per 
Cent 

Per 
Cent 

Per 

Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average      .... 

11 



85.0 

1.1 



13.4 



0.5 

270 

As  purchased      .     . 

— 

6.0 

79.9 

1.0 



12.6 



0.5 

255 

Bananas,  yellow  :  2 

Edible  portion  — 

Average      .... 

6 



75.3 

1.3 

0.6 

22.0 

(O/.o 

0.8 

460 

As  purchased      .     . 

— 

35.0 

48.9 

0.8 

0.4 

14.3 



0.6 

300 

Blackberries,      as      pur- 

chased :  3 

Average      .... 

9 



86.3 

1.3 

1.0 

10.9 

(l)2.5 

0.5 

270 

Cherries  :  4 

Edible  portion  — 

Average      .... 

16 



80,9 

1.0 

0.8 

16.7 

0)0.2 

0.6 

365 

As  purchased      .     .     . 

— 

5.0 

76.8 

0.9 

0.8 

15.9 



0.6 

345 

Cranberries,  aspurchased  : 

Average      .... 

3 



88.9 

0.4 

0.6 

9.9 

(2)/.5 

0.2 

215 

Currants,  as  purchased   . 

1 



85.0 

1.5 



12.8 



0.7 

265 

Figs,  fresh,  as  purchased: 

Average  5   .     .     .     . 

28 



79.1 

1.5 



18.8 



06 

380 

acids,  etc.,  12  per  cent.     The  edible  portion  of  1  sample  contained  protein  (NX6.25) 
0.6  and  proteids  0.4  per  cent. 

1  The  edible  portion  of  1  sample  contained  11.9  per  cent  sugar.        The  fat  was  not 
determined. 

2  The  edible  portion  of  1  sample  contained  protein  (N  X  6.25)  1.4  and  proteids 
1.2  per  cent.     The  edible  portion  of  1  sample  contained  0.1  per  cent  free  acid. 

3  One  sample  contained  protein  (N  X  6.25)  0.9  and  proteids  0.7  per  cent. 

^  The  ash  of  1  sample  contained  CaO  4.2,  K2O  57.7,  MgO  5.5,  P2Os  15.1,  Na2O 
6.8,  and  SOs  5.8  per  cent.  The  edible  portion  of  1  sample  contained  protein  (N  X 
6.25)  1.1  and  proteids  0.4  per  cent.  The  edible  portion  of  1  samplei  contained  0.1 
per  cent  free  acid.  Six  samples  contained  an  average  of  11  per  cent  sugar. 

5  The  ash  of  3  samples  contained  an  average  of  CaO  2.4,  KzO  55.8,  MgO  5.6, 
P2Oo  12.4,  and  SOs  3.9  per  cent.  Fat  not  determined. 


Chemical  Composition,  American  Food  Materials   433 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 

Continued 


P 

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VEGETABLE  FOOD  — 

Continued 

FRUITS,    BERRIES,    ETC., 

FRESH  —  Continued 

Grapes  :  l 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average  .... 

5 



77.4 

1.3 

1.6 

192 

(l)4.3 

0.5 

450 

As  purchased      .     .     . 

— 

25.0 

58.0 

1.0 

1.2 

14.4 



0.4 

335 

Huckleberries,  edible  por- 

tion   . 

1 



81.9 

0.6 

0.6 

16.6 



0.3 

345 

Lemons  :  2 

Edible  portion  — 

Average      .... 

4 



89.3 

1.0 

0.7 

8.5 

(*)M 

0.5 

205 

As  purchased      .     .     . 

— 

30.0 

62.5 

0.7 

0.5 

5.9 



0.4 

145 

Lemon  juice       .... 

22 









9.8  3 





180 

Muskmelons: 

Edible  portion    .     .     . 

1 



89.5 

0.6 



9.3 

2.1 

0.6 

185 

As  purchased      .     .     . 

1 

50.0 

44.8 

0.3 



4.6 



0.3 

90 

Nectarines  :  4 

Edible  portion    .     .     . 

1 



82.9 

0.6 



15.9 



0.6 

305 

As  purchased      .     .     . 

1 

6.6 

77.4 

0.6 



14.8 



0.6 

285 

Oranges  :  5 

Edible  portion  — 

Average      .... 

23 



86.9 

0.8 

0.2 

11.6 



0.5 

240 

As  purchased      .     .     . 

— 

27.0 

63.4 

0.6 

0.1 

8.5 



0.4 

170 

1  The  ash  of  5  samples  contained  an  average  of  CaO  5,  K2O  50.9,  MgO  3,  P2Os 
21.2,  and  SOs  4.3  per  cent. 

2  The  ash  of  2  samples  contained  an  average  of  CaO  29.9,  I&O  48.3,  MgO  4.4, 
P2O5  11.1,  and  SO3  2.8  per  cent.     Two  samples  contained  an  average  of  protein 
(N  X  6.25)  0.9  and  proteids  0.5  per  cent. 

3  Sugar  2.3,  citric  acid  7.5  per  cent. 

4  Fat  not  determined. 

5  The  ash  of  9  samples  contained  an  average  of  CaO  22.7,  KsO  48.9,  MgO  5.4, 
P2Os  12.4,  and  SOs  5.2  per  cent.     Fat  determined  in  8  samples,  the  mean  of  these 
assumed  to  be  an  average.     Eight  samples  contained  an  average  of  9  per  cent 
sugar. 

2F 


434 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


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VEGETABLE  FOOD  — 

Continued 

FRUITS,     BERRIES,     ETC., 

FRESH  —  Continued 

Pears  :  l 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .     .     .     . 

2 



84.4 

0.6 

0.5 

14.1 

0)2.7 

0.4 

295 

As  purchased      .     .     . 

— 

10.0 

76.0 

0.5 

0.4 

12.7 



0.4 

260 

Persimmons,  edible  por- 

tion 2       .... 

1 



66.1 

0.8 

0.7 

31.5 

1.8 

0.9 

630 

Pineapple,  edible  portion  3 

1 



89.3 

0.4 

0.3 

9.7 

0.4 

0.3 

200 

Plums  :  4 

Edible   portion,    aver- 

age      

3 



78.4 

1.0 



20.1 



0.5 

395 

As  purchased      .     .     . 

— 

5.0 

74.5 

0.9 



19.1 



0.5 

370 

Pomegranates,  edible  por- 

tion :  5 

Average      .... 

2 



76.8 

1.5 

1.6 

19.5 

2.7 

0.6 

460 

Prunes  :  6 

Edible   portion,    aver- 

age      

24 



79.6 

0.9 



18.9 

; 

0.6 

370 

As  purchased      .     .     . 

20 

5.8 

75.6 

0.7 



17.4 



0.5 

335 

Raspberries,  red,  as  pur- 

chased 7       ... 

1 



85.8 

1.0 

—  — 

12.6 

2.9 

0.6 

255 

Raspberries,  black,  edible 

portion  : 

Average      .... 

3 



84.1 

1.7 

1.0 

12.6 



0.6 

310 

1  One  sample  contained  protein  (N  X  6.25)  0.6  and  proteids  0.3  per  cent. 

2  Contained  glucose  13.5,  cane  sugar  1  per  cent. 

3  Contained  protein  (N  X  6.25)  0.4  and  proteids  0.1  per  cent. 

4  The  edible  portion  contained  13.2  per  cent  sugar     Fat  not  determined. 

5  Two  samples  contained  an  average  of  glucose  11,  of  cane  sugar  0.7  per  cent. 

6  The  ash  of  the  edible  portion  of  3  samples  contained  an  average  of  CaO  4.7, 
K2O  63.8,  MgO  5.5,  P2Os  14.1,  and  SOs  2.7  per  cent.     Edible  portion  of  20  samples 
contained  an  average  of  16.1  per  cent  sugar.     Fat  was  not  determined. 

7  Fat  not  determined. 


Chemical  Composition,  American  Food  Materials  435 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


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VEGETABLE  FOOD  — 

Continued 

FRUITS,     BERRIES,      ETC., 

FRESH  —  Continued 

Per 

Per 

Per 

Per- 

Per 

Per 

Per 

Cal- 

Raspberry  juice,    edible 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

portion   .... 

i 



49.3 

0.5 



49.9i 



0.3 

935 

Strawberries  :  2 

Edible  portion  — 

Average      .... 

22 



90.4 

1.0 

0.6 

7.4 

(a)l-4 

0.6 

180 

As  purchased      ...     . 

— 

5.0 

85.9 

0.9 

0.6 

7.0 



0.6 

175 

Watermelons  :  3 

Edible  portion  — 

Average      .... 

2 



92.4 

0.4 

0.2 

6.7 



0.3 

140 

As  purchased      .     .     . 

— 

59.4 

37.5 

0.2 

0.1 

2.7 



0.1 

60 

Whortleberries,    as   pur- 

chased *       .     .     . 

1 



82.4 

0.7 

3.0 

13.5 

3.2 

0.4 

390 

FRUITS,    ETC.,   DRIED 

Apples,  as  purchased  :  5 

Average      .     »    ., 

3 



28.1 

1.6 

2.2 

66.1 



2.0 

1350 

Apricots,  as  purchased  :  6 

Average      .... 

2 



29.4 

4.7 

1.0 

62.5 



2.4 

1290 

Citron,  as  purchased  : 

Average      .-..,, 

2 



19.0 

0.5 

1.5 

78.1 



0.9 

1525 

1  Probably  sweetened. 

2  Four  samples  contained  an  average  of  protein  (N  X  6.25)   0.7  and  proteids 
0.5  per  cent.     Fifteen  samples  contained  an  average  of  glucose  5.5  and  free  acid, 
calculated  as  malic  acid,  1.4  per  cent. 

3  In  one  melon  the  rind  was  55.8  of  the  whole,  the  pulp  6.9,  the  seeds  2.2,  and 
the  juice  35.1  per  cent.     The  edible  portion  of  1  sample  contained  protein  (N  X  6.25) 
0.9  and  proteids  0.3  per  cent. 

4  Contained  protein  (N  X  6.25)  0.7  and  proteids  0.5  per  cent. 

5  One  sample  contained  2  per  cent  free  acid  calculated  as  sulfuric  acid. 

8  One  sample  contained  1.5  per  cent  free  acid  calculated  as  sulfuric  acid. 


436 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


FOOD  MATERIALS 

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VEGETABLE  FOOD  — 

Continued 

FRUITS,      ETC.,      DRIED  — 

Continued 

Currants,  Zante,  as  pur- 
chased : 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

Average      .... 

4 



17.2 

2.4 

1.7 

74.2 



4.5 

1495 

Dates  : 

Edible  portion  — 

Average      .... 

2 



15.4 

2.1 

2.8 

78.4 



1.3 

1615 

As  purchased      .     .     . 

— 

10.0 

13.8 

1.9 

2.5 

70.6 



1.2 

1450 

Figs,  as  purchased  :  l 

Average      .... 

3 



18.8 

4.3 

0.3 

74.2 



2.4 

1475 

Grapes,  ground,  as  pur- 

chased 2       ... 

1 



34.8 

2.8 

0.6 

60.5 

3.7 

1.2 

1205 

Pears,  as  purchased    . 

1 

,  

16.5 

2.8 

5.43 

72.9 



2.4 

1635 

Prunes  :  4 

Edible  portion  — 

Average      .... 

15 



22.3 

2.1 



73.3 



2.3 

1400 

As  purchased      .     .     . 

— 

15.0 

19.0 

1.8 



62.2 



2.0 

1190 

Raisins  : 

Edible  portion  — 

Average      .... 

3 



14.6 

2.6 

3.3 

76.1 



3.4 

1605 

As  purchased      .     .     . 

— 

10.0 

13.1 

2.3 

3.0 

68.5 



3.1 

1445 

Raspberries,  as  purchased 

1 



8.1 

7.3 

1.8 

80.2 



2.6 

1705 

FRUITS,    ETC.,    CANNED  ; 

AND   JELLIES,    PRE- 

SERVES,   ETC. 

Apples,  crab,  as  purchased 

1 



42.4 

0.3 

2.4 

54.4 



0.5 

1120 

Apple  sauce,  as  purchased 

1 



61.1 

0.2 

0.8 

37.2 



0.7 

730 

1  One  sample  contained  0.4  per  cent  free  acid  calculated  as  sulfuric  acid. 

2  Contained  0.8  per  cent  free  acid  calculated  as  sulfuric  acid  and  1.3  per  cent 
tannin. 

3  The  percentage  of  fat  given  is  evidently  too  high. 

4  Twelve  samples  contained  an  average  of  sugar  25.4  and  free  acid  0.3  per  cent, 
calculated  as  sulfuric  acid.     Fat  not  determined. 


Chemical  Composition,  American  Food  Materials  437 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


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VEGETABLE  FOOD  — 

Continued 

FRUITS,  ETC.,  CANNED; 

AND   JELLIES,    PRE- 

SERVES,   ETC.  

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Continued 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Apricots,  as  purchased    . 

1 



81.4 

0.9 



17.3 



0.4 

340 

Apricot    sauce,    as    pur- 

chased   .... 

1 



45.2 

1.9 

1.3 

48.8 



2.8 

1000 

Blackberries,      as      pur- 

chased   .... 

1 

, 

40.0 

0.8 

2.1 

56.4 



0.7 

1150 

Blueberries,  as  purchased 

Average      .... 

3 



85.6 

0.6 

0.6 

12.8 



0.4 

275 

Cherries,  as  purchased    . 

1 



77.2 

1.1 

0.1 

21.1 



0.5 

415 

Cherry  jelly: 

1st    quality,    as    pur- 

chased   .... 

1 



21.0 

1.1 



77.2 

. 

0.7 

1455 

2d     quality,     as    pur- 

chased    .... 

1 



38.4 

1.2 



59.8 



0.6 

1135 

Figs,     stewed,     as    pur- 

chased   .... 

1 



56.5 

1.2 

0.3 

40.9 



1.1 

785 

Grape    butter,    as    pur- 

chased   .     .     .     . 

1 



36.7 

1.2 

0.1 

58.5 



3.5 

1115 

Marmalade  (orange  peel), 

as  purchased  l 

1 



14.5 

0.6 

0.1 

84.5 



0.3 

1585 

Peaches,  as  purchased  : 

Average      .... 

3 



88.1 

0.7 

0.1 

10.8 



0.3 

220 

Pears,  as  purchased  : 

Average      .... 

4 



81.1 

0.3 

0.3 

18.0 



0.3 

355 

Pineapples,  as  purchased 

1 



61.8 

0.4 

0.7 

36.4 



0.7 

715 

Prune     sauce,     as     pur- 

chased   .... 

1 



76.6 

0.5 

0.1 

22.3 



0.5 

430 

Strawberries,  stewed,  as 

purchased   .     .     . 

1 



74.8 

0.7 



24.0 

0.5 

460 

1  Fifteen  samples  of  marmalade  contain  an  average  of  water  30.8,  sugar  32.8, 
invert  sugar  32.3,  glucose  14.2,  acid  0.5,  and  undetermined  3.6  per  cent. 


438 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


0-3 

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VEGETABLE  FOOD  — 

Continued 

FRUITS,    ETC.,    CANNED  ', 

AND   JELLIES,   PRE- 

SERVES,  ETC.  

Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Tomato    preserves,     as 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

purchased   ... 

1 



40.9 

0.7 

0.1 

57.6 



0.7 

1090 

NUTS 

AJmpnds  :  l 

Edible  portion  — 

Average      .... 

11 

_ 

4.8 

21.0 

54.9 

17.3 

2.0 

2.0 

3030 

As  purchased      .     .     . 

45.0 

2.7 

11.5 

30.2 

9.5 



1.1 

1660 

Beechnuts  : 

Edible  portion    .     .     . 

1 



4.0 

21.9 

57.4 

13.2 



3.5 

3075 

As  purchased 

1     40.8 

2.3 

13.0 

34.0 

7.0 



2.1 

1820 

"Biotes"  (acorns),  (Quer- 

cus  emoryi)  : 

Edible  portion    .     . 

1 



4.1 

8.1 

37.4 

48.0 



2.4 

2620 

As  purchased      .     .     . 

1 

35.6 

2.6 

5.2 

24.1 

30.9 



1.6 

1690 

Brazil   nuts    (Bertholletia 

excelsd)  : 

Edible  portion    .     .     . 

1 



5.3 

17.0 

66.8 

7.0 



3.9 

3265 

As  purchased 

1 

49.6 

2.6 

8.6 

33.7 

3.5 



2.0 

1655 

Butternuts  (Juglans  cin- 

erea)  : 

Edible  portion    . 

1 



4.4 

27.9 

61.2 

3.5 



2.9 

3165 

As  purchased      .     . 

1 

86.4 

0.6 

3.8 

8.3 

0.5 



0.4 

430 

Chestnuts,  fresh  :  2 

Edible  portion  — 

Average      .... 

9 



45.0 

6.2 

5.4 

42.1 

1.8 

1.3 

1125 

1  Fresh  almonds  contain  from  40  to  42  per  cent  water.     The  ash  of  the  kernel 
contains  CaO  14.5,  MgO  18.3,  Na2O  1.8,  KaO  11,   MnCfe  0.3,  Fe2O3+Al2O3  0.8, 
PiOs  48.1,  SOs  4.6,  SiO2  0.2,  and  Cl  0.3  per  cent. 

2  The  ash  of  2  samples  contained  an  average  of  CaO  4.6,  MgO  8,  NaaO2  1.2, 


Chemical  Composition,  American  Food  Materials   439 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


II 

111 

FOOD  MATERIALS 

h 

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VEGETABLE  FOOD  — 

Continued 

NUTS  —  Continued 

Chestnuts,    fresh  —  Con- 
tinued 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Per 
Cent 

Cal- 
ories 

As  purchased      .     .     . 

9 

16.0 

37.8 

5.2 

4.5 

35.4 



1.1 

945 

Chestnuts,  dried  : 

Edible  portion  — 

Average      ?    .     .     . 

8 



5.9 

10.7 

7.0 

74.3 

2.7 

3.3 

1875 

As  purchased      .     .     . 

8 

24.0 

4.5 

8.1 

5.3 

56.4 



1.7 

1425 

Coconuts  : 

Edible  portion    .     .     . 

1 



14.1 

5.7 

50.6 

27.9 



1.7 

2760 

As  purchased      .     .     . 

1 

48.8i 

7.2 

2.9 

25.9 

14.3 



0.9 

1413 

Coconut    without    milk, 

as  purchased    .     . 

1 

37.3  2 

8.9 

3.6 

31.7 

17.5 



1.0 

1730 

Coconut    milk,    as    pur- 

chased   .... 

1 



92.7 

0.4 

1.5 

4.6 



0.8 

155 

Coconut,     prepared,     as 

purchased  : 

Average      .     .  '  ..     .' 

3 



3.5 

6.3 

57.4 

31.5 



1.3 

3135 

Filberts  : 

Edible  portion    .     .     . 

1 



.   3.7 

15.6 

65.3 

13.0 



2.4 

3290 

As  purchased      .     .     . 

1 

52.1 

1.8 

7.5 

31.3 

6.2 



1.1 

1575 

Hickory  nuts  : 

Edible  portion    .     .     . 

1 



3.7 

15.4 

67.4 

11.4 



2.1 

3345 

As  purchased      .     .     . 

1 

62.2 

1.4 

5.8 

25.5 

4.3 



0.8 

1265 

Lichi  nuts: 

Edible  portion    .     .     . 

1 



17.9 

2.9 

0.2 

77.5 



1.5 

1505 

As  purchased      .     .     . 

1 

41.6 

10.5 

1.7 

0.1 

45.2 



0.9 

875 

Peanuts  : 

Edible  portion  — 

Average      .... 

* 

9.2 

25.S 

38.6 

24.4 

2.5 

2.0 

3560 

As  purchased      .     .     . 

24.5 

(>.<> 

10..) 

29.1 

18.5 

1.5 

1935 

K2O  48.7,    MnO2   0.2,    Fe2O  +  AbOs    0.4,    P2Os    23.5,    820    12.8,    SiO2  0.2,   and 
Cl  0.3  per  cent. 

i  Milk  and  shell.  2  Shell  only. 


440 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


(xTJ 

fc.J  1 

FOOD  MATERIALS 

K  £ 

JZ 

Its 

||| 

s| 

3  S 

H 

M 

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^"Pn 

II 

I 

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0 

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JI.I 

P.B 

• 

GO 

j 

* 

« 

^ 

* 

P* 

£ 

p=t  * 

VEGETABLE  FOOD  — 

Continued 

NUTS  —  Continued 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Peanut  butter,    as   pur- 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

chased    .... 

2 



2.1 

29.3 

46.5 

-17.1 



5.0  ' 

2825 

Pecans,  polished  : 

Edible  portion   .     .     . 

1 



3.0 

11.0 

71.2 

13.3 



1.5 

3455 

As  purchased      .     .     . 

1 

53.2 

1.4 

5.2 

33.3 

6.2 



0.7 

1620 

Pecans,  unpolished  : 

Edible  portion    .     .     . 

1 



2.7 

9.6 

70.5 

15.3 



1.9 

3435 

As  purchased      .     .     . 

1 

46.3 

1.5 

5.1 

37.9 

8.2 



1.0 

1846 

Pine  nuts  : 

Pignolias,   edible   por- 

tion     

1 



6.4 

33.9 

49.4 

6.9 



3.4 

2845 

Piniones  (Pinus  mono- 

phylla)  — 

Edible  portion     .     . 

1 



3.8 

6.5 

60.7 

26.2 



2.8 

3170 

As  purchased       .     . 

1 

41.7 

2.2 

3.8 

35.4 

15.3 



1.6 

1850 

Pinon  (Pinus  edulis)  — 

Edible  portion     .     . 

1 



3.4 

14.6 

61.9 

17.3 



2.8 

3205 

As  purchased       .     . 

1 

40.6 

2.0 

.8.7 

36.8 

10.2 



1.7 

1905 

Sabine  pine  nut  (Pinus 

sabiniana)  — 

Edible  portion     .     . 

1 



5.1 

28.1 

53.7 

8.4 



4.7 

2945 

As  purchased       .     . 

1 

77.0 

1.2 

6.5 

12.3 

1.9 



1.1 

675 

Pistachios  : 

First  quality,  shelled, 

edible  portion 

1 



4.2 

22.3 

54.0 

16.3 



3.2 

2995 

Second  quality,  shelled, 

edible  portion 

1 

-  

4.3 

22.8 

54.9 

14.9 



3.0 

3020 

Walnuts,  California  :  2 

Edible  portion    .     .     . 

1 



2.5 

18.4 

64.4 

13.0 

14 

1.7 

3300 

As  purchased      .     .     . 

1 

73.1 

0.7 

4.9 

17.3 

3.5 



0.5 

885 

1  1  per  cent  salt. 

2  Fresh  walnuts  contain  from  20  to  27  per  cent  water.     The  ash  of  7  samples 
of  kernel  contained  an  average  of  CaO  5.6,  MgO  16.6,  Na->O  1,  KaO  12.7,  MnCh  0.3, 
FetO»  +  Al2Os  3.2,  P2Os  57.8,  SO3  1.3,  SiO2  0.7,  and  Cl  0.7  per  cent. 


Chemical  Composition,  American  Food  Materials  441 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


*"% 

**H    73  x-s. 

O"y 

J-B  $> 

FOOD  MATERIALS 

o§ 

W  J 

. 

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s| 

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i 

H 

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P* 

A 

fe 

P 

•1 

< 

£  * 

VEGETABLE  FOOD  — 

Continued 

NUTS  —  Continued 

Walnuts,          California, 
black  : 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

2 



2.5 

27.6 

56.3 

11.7 

/.7 

1.9 

3105 

As  purchased      .     .     . 

— 

74.1 

0.6 

7.2 

14.6 

3.0 



0.5 

805 

Walnuts,  California,  soft 

shell  : 

Edible  portion  — 

Average      .... 

4 



2.5 

16.6 

63.4 

16.1 

2.0 

1.4 

3285 

As  purchased      .     .     . 

— 

58.1 

1.0 

6.9 

26.6 

6.8 



0.6 

1375 

"Malted  nuts,"  as  pur- 

chased   .... 

1 



2.6 

23.7 

27.6 

43.9 



2.2 

2240 

MISCELLANEOUS 

Chocolate,  as  purchased  : 

Average      .... 

2 



5.9 

12.9 

48.7 

30.3 



2.2 

2860 

Cocoa,  as  purchased  : 

Average      .... 

3 



4.6 

21.6 

28.9 

37.7 



7.2 

2320 

Cereal  coffee  infusion  (1 

part  boiled  in  20 

parts  water)  * 

5 



98.2 

0.2 



1.4 



0.2 

30 

Yeast,     compressed^    as 

purchased  .     .     . 

1 



65.1 

11.7 

0.4 

21.0 

1.8 

625 

1  The  average  of  five  analyses  of  cereal  coffee  grain  is:  Water  6.2,  protein  13.3, 
fat  3.4,  carbohydrates  72.6,  and  ash  4.5  per  cent.  Only  a  portion  of  the  nutrients 
however,  enter  into  the  infusion.  The  average  in  the  table  represents  the  available 
nutrients  in  the  cereal  coffee  infusion.  Infusions  of  genuine  coffee  and  of  tea  con- 
tain practically  no  nutrients. 


442 


Principles  of  Human  Nutrition 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS 
Continued 


FOOD  MATERIALS 

NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

9 

< 

H 

P  a 
i->  fc 

*l 

H« 

1* 

N  X  6.25 

By  Differ- 
ence 

UNCLASSIFIED  FOOD 

MATERIALS 

ANIMAL   AND   VEGETABLE 

Soups,  home-made. 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Beef soup,  as  purchased  : 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

3 



92.9 

4.4 



0.4 

1.1 

1.3 

120 

Bean  soup,  as  purchased  : 

1 



84.3 

10.5 



1.4 

9.4 

1.7 

295 

Chicken    soup,    as    pur- 

chased   .... 

1 



84.3 

10.5 



0.8 

2.4 

2.0 

275 

Clam   chowder,   as  pur- 

chased : 

Average      .... 

3 



88.7 

1.8 



0.8 

6.7 

3.0 

195 

Meat  stew,  as  purchased  : 

Average      .... 

5 



84.5 

4.6 



4.3 

5.5 

1.1 

370 

Soups,  canned. 

Asparagus,  cream  of,  as 

purchased   . 

1 



87.4 

2.5 



3.2 

5.5 

1.4 

285 

Bouillon,  as  purchased  : 

Average      .... 

3 



96.G 

3.3 



0.1 

0.3 

0.9 

50 

Celery,  cream  of,  as  pur- 

chased   .... 

1 

—  <  — 

88.6 

2.1 



2.8 

5.0 

1.5 

250 

Chicken  gumbo,  as  pur- 

chased : 

Average      .... 

3 



89.3 

3.8 



0.9 

4.7 

1.4 

195 

Chicken    soup,    as    pur- 

chased : 

Average      .... 

2 



93.8 

3.6 



0.1 

1.5 

1.0 

100 

Consomme,  as-purchased 

1 

..flfi,n  , 

_2.5 





0.4 

1.1 

55 

Cream,  corn  of,  as  pur- 

chased   .... 

1 



86.8 

2.5 



1.9 

7.8 

1.0 

270 

Julienne,  as  purchased    . 

1 



95.9 

2.7 





0.5 

0.9 

60 

Mock     turtle,    as     pur- 

chased : 

Average      .... 

3 



89.8 

5.3 



0.9 

3.8 

1.3 

185 

Mulligatawny,    as    pur- 

chased : 

Average      .... 

3 



89.3 

3.7 



0.1 

5.7 

1.3 

180 

Chemical  Composition,  American  Food  Materials  443 


CHEMICAL  COMPOSITION  OF  AMERICAN  FOOD  MATERIALS  — 
Continued 


FOOD  MATERIALS 

I  NUMBER  OF 
ANALYSES 

REFUSE 

WATER 

PROTEIN 

1 

TOTAL  CARBO- 
HYDRATES 

1 

w 

P  Q 

41 

^ 

H 

|Q 

<N 

co 
X 

g 

1, 

°g 
>> 

pq 

UNCLASSIFIED  FOOD 

MATERIALS  —  Continued 

ANIMAL   AND   VEGETABLE 

—  Continued 

Soups,  canned  —  Continued 

Oxtail  : 

Per 

Per 

Per 

Per 

Per 

Per 

Per 

Cal- 

Edible portion  — 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

Cent 

ories 

Average      .... 

2 



88.8 

4.0 



1.3 

4.3 

1.6 

210 

As  purchased      .     .     . 

1 

1.8 

87.8 

3.8 



0.5 

4.2 

1.9 

170 

Pea  soup,  as  purchased  : 

Qf*    4| 

9    i* 

A     M 

Average      .... 
Pea,  cream  of  green,  as 

5>O»5J 

«f»o 

U.7 

7.6 

1.2 

235 

purchased   . 

1 

T. 

87.7 

2.6 



2.7 

5.7 

1.3 

270 

Tomato    soup,    as    pur- 

chased : 

Average      .... 

2 



90.0 

1.8 



1.1 

5.6 

1.5 

185 

Turtle,    green,    as    pur- 

chased    .... 

1 



86.6 

6.1 



1.9 

3.9 

1.5 

265 

Vegetable,  as  purchased 

1 



95.7 

2.9 





0.5 

0.9 

65 

Miscellaneous 

Hash,  as  purchased    . 

1 



80.3 

6.0 



1.9 

9.4 

2.4 

365 

"Infants'    and    invalids' 

foods,"     as     pur- 

chased :  1 

Average      .... 

22 



6.0 

12.7 



3.3 

76.2 

1.8 

1795 

Mincemeat,  commercial, 

as  purchased  : 

Average      .... 

3 



27.7 

6.7 



1.4 

60.2 

4.0 

1305 

Mincemeat,  home-made, 

as  purchased  : 

Average      .... 

3 



54.4 

4.8 



6.7 

32.1 

2.0 

970 

Salad,  ham,  as  purchased 

1 



69.4 

15.4 



7.6 

5.6 

2.0 

710 

Sandwich,    egg,    as   pur- 

chased   .... 

1 



41.4 

9.6 



12.7 

34.5 

1.8 

1355 

Sandwich,     chicken,     as 

purchased   .     .     . 

1 



48.5 

12.3 



5.4 

32.1 

1.7 

1055 

1  This  includes  malted  milk,  infants'  foods,  and  similar  preparations  which  are 
sold  under  various  trade  names,  but  are  similar  in  composition. 


INDEX 


Absorption,  maximum,  112. 

Acids,  77;   fatty,  81. 

Age,  relation  to  diet,  215. 

Air,  carbon  dioxid  in,  7. 

Albuminoids,  52. 

Albumins,  47;  examples  of,  48. 

Alcohol,  as  food,  311 ;  in  nutri- 
tion, 309 ;  relation  to  work, 
310. 

Amandin,  50. 

Amides,  61. 

Amylopsin,  1Q4. 

Animal,  ash  elements  in,  18 ;  com- 
bination of  ash  elements  in,  40 ; 
distribution  of  ash  compounds  in 
combinations,  39  ;  elements  in,  17  ; 
water  in,  31. 

Animal  life,  relation  to  plant,  4. 

Arabinose,  74. 

Ash,  33  ;  combination  elements  in, 
34  ;  compounds  in  animal  bodies, 
38  ;  distribution  of,  compounds  in 
animal  body,  39 ;  elements,  in 
plants,  35  ;  elements,  in  plant  and 
animal,  40 ;  influence  of  manu- 
facturing and  cooking  on,  37 ; 
plant,  elements  in,  16 ;  varia- 
tions in  species  of  plants,  36. 

Assimilation,  84. 

Avenalin,  50. 

Bacteria,  86 ;    effect  on  food,  343 ; 

in  digestive  tract,  90 ;    in  feces, 

114  ;  in  foods,  250  ;   in  intestines, 

250;   intestinal,  105. 
Bile,   the,    102;    secretion  of,    103; 

salts  in,  102. 
Blood,     the,     127;     corpuscles    in, 

128. 


Blood  flow,  relation  to  work,  220. 
Brain    power,     relation     to    phos- 
phorus, 150. 
Breathing,  object  of,  134. 

Calcium,  function,  14 ;   sources,  14. 

Calorimeter,  respiration,  145. 

Candy,  for  children,  295. 

Capillaries,  function  of,  110. 

Carbohydrates,  65;  as  protein 
sparers,  172 ;  classification,  64 ; 
digestibility  of,  116;  elementary 
composition  of,  63 ;  functions 
of,  156 ;  physiologically  econom- 
ical, 170;  source  of  fats,  156. 

Carbon,  circulation  of,  8;  ex- 
amples of,  7 ;  in  crops,  8 ;  di- 
oxid, elimination  of,  138;  dioxid, 
in  air,  7. 

Carbonic  acid,  in  cooking,  312. 

Cellulose,  75. 

Child,  diet  for,  293,  295;  feeding 
of,  266,  293;  meals  for,  297; 
nutrition'of,  260. 

Childhood,  relation  to  diet,  214. 

Chlorine,  13. 

Circulation,  of  blood,  132. 

Collagen,  52. 

Compounds,  classification,  24. 

Condiments,  influence  on  digestion, 
124. 

Cooking,  effect  on  foods,  314 ; 
influence  on  ash  constituents,  37  ; 
influence  on  digestion,  124; 
influence  on  nutritive  value,  319; 
influence  on  food  functions,  258; 
losses  from,  315;  prevents  dis- 
ease, 337 ;  vegetables,  losses 
from,  318. 


445 


446 


Index 


Corpuscles,  blood,  128. 
Corylin,  50. 
Creatin,  62. 
Creatinin,  63. 
Crops,  carbon  in,  8. 
Crude  fiber,    75 ;  influence    on    di- 
gestibility, 122. 

Dextrans,  74. 

Dextrin,  75. 

Dextrose,  67. 

Diastases,  92. 

Diet,  for  child,  294 ;  for  pregnant 
woman,  265 ;  ill-considered, 
209  ;  insufficient,  272  ;  minimum, 
189;  regulation  of,  179,  200; 
regulation  of  dry  matter  in,  206 ; 
relation  to  childhood,  214 ;  rela- 
tion to  expenditure,  226 ;  rela- 
tion to  life  conditions,  214 ; 
relation  to  old  age,  215 ;  re- 
lation to  sex,  217;  relation  to 
temperament,  218  ;  relation  to 
weight,  216 ;  relation  to  work, 
218  ;  restriction  of,  189  ;  simple, 
241. 

Dietaries,  based  on  experience,  187 ; 
individual  demands,  188 ;  for 
milk  secretion,  272 ;  standard, 
180-181 ;  study  of,  181. 

Digestibility,  meaning  of,  118. 

Digestion,  84 ;  different  classes  of 
food,  125 ;  effect  of  work  on,  123  ; 
factors  influencing,  117;  in 
intestines,  101 ;  influence  of 
amount  eaten,  123 ;  influence 
of  condiments,  124 ;  influence 
of  cooking  on,  124  ;  influence  of 
crude  fiber,  122 ;  influence,  of 
individual,  125 ;  influence  of 
mastication,  122 ;  influence  of 
relish  for  food,  123  ;  in  stomach, 
95,  98 ;  relation  of  food  com- 
pounds to,  114;  relation  to 
food,  118. 

Di-saccharides,  68. 


Dry  matter,  regulation  of,  in  diet, 
206. 

Edestin,  50. 

Elements,  ash,  combinations  of, 
34 ;  ash,  in  animal  body,  18 ; 
ash,  in  plants,  35 ;  determina- 
tion of  those  essential,  142  ; 
distribution  in  compounds,  25 ; 
in  animals,  17 ;  in  plant  ash,  16 ; 
in  plants,  15 ;  number  related 
to  nutrition,  6. 

Embryo,  composition  of,  261. 

Energy,  available,  163 ;  forms  of, 
148;  from  food,  157;  illustra- 
tions of,  158 ;  in  food  compounds, 
161;  manifestations  of,  159; 
measurement  of,  147;  net,  164; 
relations  of,  in  nutrients,  167 ; 
requirement,  how  determined, 
193  ;  requirement,  reduction  of, 
193  ;  stored  by  plant,  4  ;  stored 
in  plants,  160 ;  source  of,  173  ; 
unit  of,  161 ;  use  during  preg- 
nancy, 263 ;  use  during  sleep, 
191 ;  use  when  fasting,  191 ; 
values,  166. 

Enterokinase,  105. 

Enzyms,  91 ;  gastric,  96 ;  in  pan- 
creatic juice,  103. 

Erepsin,  105. 

Ether  extract,  64,  82. 

Excelsin,  50. 

Excretion,  avenues  of,  173. 

Extractives,  61. 

Extracts,  commercial,  302 ;  fluid, 
301 ;  meat,  301. 

Fats,  77 ;  as  protein  sparers,  172 ; 
digestibility  of,  117,  120;  from 
carbohydrates,  156 ;  functions 
of,  157 ;  in  grains  and  seeds,  78 ; 
individual,  80 ;  in  milk,  81 ; 
nature  and  kind,  79 ;  physical 
properties,  80. 

Fatty  acitis,  81. 


Index 


447 


Feces,  113. 

Fermentations,  results  of,  88. 

Ferments,  86  ;  conditions  of  growth 
88 ;  distribution,  87 ;  organized, 
86  ;  organized,  manner  of  action 
89 ;  organized,  structure,  87 
unorganized,  91 ;  unorganized,  ac- 
tion of,  91. 

Fetus,  composition  of,  261 ;  growth 
of,  260;  nourishment  of,  260; 
sources  of  growth,  262. 

Fibrin,  50. 

Fibrinogen,  50. 

Fibroin,  53. 

Food,  absorption  of,  109 ;  avail- 
ability for  digestion,  173 ;  bal- 
ance, 146,  175;  changes  through 
digestion,  85  ;  compounds,  func- 
tions of,  142  ;  compounds,  inter- 
relation of,  170 ;  consumption, 
basis  for  dietaries,  186 ;  con- 
sumption, influence  of  condition, 
186 ;  demands  during  preg- 
nancy, 263  ;  digestion  of,  107  ; 
economy  in  buying,  240 ;  energy 
values  of,  166 ;  expensive  ser- 
vice, 244 ;  fate  of  excess,  188 ; 
how  absorbed,  111 ;  how  used, 
148;  of  mother,  effect  on  child, 
274  ;  preparation'  of,  240  ;  preser- 
vation of,  343  ;  relation  to  body 
type,  194 ;  relation  to  social 
welfare,  243  ;  requirements,  175  ; 
selection  of,  200,  236  ;  standards, 
limitations  of,  200 ;  source  of 
building  material  173;  source 
of  energy,  157,  173  ;  use  of,  135  ; 
uses  of  digested,  174 ;  waste  of, 
244. 

Foods,  artificial,  210 ;  bacteria  in, 
250;  breakfast,  304;  breakfast, 
composition,  305  ;  breakfast,  cost 
of,  307;  breakfast,  digestibility 
of,  305;  breakfast,  false  claims 
for,  307  ;  breakfast,  preparation 
of,  305  ;  breakfast,  sources,  304  ; 


canning  of,  346;  carbohydrate, 
203  ;  cheap,  229  ;  classes  of,  201 ; 
classification  of,  204 ;  commer- 
cial, 301 ;  composition  of,  351- 
443 ;  containing  uric  acid 
formers,  252;  contamination  of, 
320;  cost  of,  226;  cost  of  dis- 
tribution, 238;  costly,  229; 
depredations  of  insects,  347  ; 
dry,  204  ;  dry,  care  of,  344  ;  dry, 
water  in,  31 ;  effect  of  cooking 
on,  314  ;  effect  on  milk  secretion, 
272;  fat,  203;  fat  rich,  79; 
infant,  289 ;  infant,  composition 
of,  290  ;  infant,  facts  about,  292  ; 
infant,  standard  for,  293  ;  infant, 
starch  in,  292 ;  manufactured, 
205 ;  moist,  care  of,  343  ;  prep- 
aration of,  312 ;  preservatives 
for,  338;  preserving  of,  346; 
protein,  202  ;  purins  in  vegetables, 
252  ;  raw,  257  ;  raw,  digestibility 
of,  258  ;  raw,  mastication  of,  258  ; 
sanitation  of,  320 ;  storage  of, 
345 ;  watery,  203. 

Fruit,  source  of  infection,  337. 

Fuel,  efficiency  with  man,  221. 

jralactans,  74. 

jalactose,  68. 

jastric  juice,  the,  95. 

Gelatins,  53. 

51iadin,  52. 

Globulins,  48  ;   common  in  animals, 

50  ;   in  plants,  49. 
Jlucase,  92. 
jtlutenins,  52. 
jlycin,  50. 
jlycogen,  73,  139. 
*rape  sugar,  67. 

Haemoglobin,  128. 
Health,  relation  to  protein,  197. 
Heart,  the,  130. 

Heat,     action     upon     foods,     314; 
regulation  of,  168  ;  relations,  167. 


448 


Index 


Histones,  53. 
Hordein,  52. 

Hydrogen,  relation  to  living  organ- 
isms, 10 ;  sources,  10. 

Ice,  disease  germs  in,  333 ;  rela- 
tion to  health,  332. 

Indol,  106. 

Infant,  effect  of  medicines  on,  276 ; 
feeding,  precautions  in,  277. 

Infants,  artificial  feeding  of,  278 ; 
foods  for,  289. 

Inosite,  74. 

Insects,  depredations  on  foods,  347. 

Intestinal  juices,  105. 

Intestines,  bacteria  in,  250 ;  diges- 
tion in,  101. 

Invertase,  92. 

Iron,  compounds  of,  14 ;  demand 
for,  14. 

Lactase,  92. 

Lactation,  period  of,  269. 

Lacteals,    function    in    absorption, 

109. 

Lactose,  70. 
Lecithins,  82. 
Leucocytes,  129. 
Levulans,  74. 
Levulose,  68. 

Liver,  the,  139 ;   function  of,  139. 
Living,   cost  of,  237 ;    examples  of 

simple,  242. 

Lunches,  comparison  of,  211. 
Lungs,  the,  133. 

Maltose,  70. 

Man,  efficiency  as  a  machine,  221. 

Mannans,  74. 

Mastication,  92. 

Matter,  classes  of,  20  ;  combustible, 

non-combustible,     21 ;      organic, 

inorganic,  22. 
Maysin,  50. 
Meals,  cheap,  231 ;    elaborate,  241 ; 

costly,  231. 


Measurements,  physiological,  144; 
physiological,  how  made,  145. 

Meat,  baking,  losses  from,  316; 
boiling,  losses  from,  316 ;  eating 
of,  256 ;  extract,  301 ;  extracts, 
commercial,  302 ;  frying,  losses 
from,  316 ;  roasting,  losses  from, 
316;  toxins,  338;  tubercular, 
335  ;  unhealthy,  334  ;  juices,  301. 

Meats,  cuts  of,  348 ;  losses  from 
cooking,  315. 

Medicines,  effects  on  child,  276. 

Milk,  abnormal,  273;  adulteration 
of,  323;  cow's,  care  of,  328; 
cow's,  compared  with  human, 
278;  cow's,  curdling  of,  282; 
cow's,  effect  of  food  on,  275 ; 
cow's,  disease  germs  in,  326  ; 
cow's,  germ  life  in,  325 ;  cow's, 
how  modified,  322 ;  cow's,  hu- 
manizing, 283 ;  cow's,  infection 
of,  327 ;  cow's,  modifying  of, 
284 ;  cow's,  pasteurization  of, 
329 ;  cow's,  physical  condition, 
282 ;  cow's,  sanitation  of,  321 ; 
goat's,  as  infant  food,  287  ; 
human,  266  ;  human,  analyses  of, 
267 ;  human,  compared  with 
cow's,  278 ;  human,  compounds 
in,  280  ;  human,  curdling  of,  282  ; 
human,  effect  of  individuality, 
270 ;  human,  physical  condition, 
282;  mother's,  266;  mother's, 
conditions  affecting,  269  ;  normal, 
322 ;  products  of,  toxic,  338;  secre- 
tion, demands  on  food,  270  ;  secre- 
tion, effect  of  food,  272  ;  secretion, 
insufficient  diet,  272 ;  secretion, 
necessary  dietary,  272  ;  solids,  re- 
moval of,  325 ;  standards,  324. 

Milk  fats,  81. 

Milling,  influences  on  ash  constit- 
uents, 37. 

Mineral  compounds,  elimination 
of,  138;  foods  supplying,  151; 
functions  of,  149. 


Index 


449 


Mono-saccharides,  67. 
Mouth,  the,  92. 
Myosin,  50. 

Nitrogen,  10;  compounds,  relation 
to  life,  41 ;  protein  determina- 
tion of,  42;  importance  of,  11; 
loss  and  gain,  11-12  ;  sources,  11. 

Nitrggpn  free  extract,  64. 

Non-proteins,  61. 

Nutrients,  changes  during  absorp- 
tion, 111;  cost  of,  228;  energy 
relations  of,  167 ;  entrance  into 
blood,  133;  functions  of,  147; 
individual,  changes  through  di- 
gestion, 85 ;  interchangeable, 
176 ;  study  of  functions  of, 
143. 

Nutrition,  alcohol  in,  309  ;  laws  of, 
173  ;  of  man,  elements  involved, 
6 ;  minimum,  192. 

Obesity,  222. 

Oils,  77. 

Ova  albumin,  48. 

Oxygen,  function  of,  136 ;    relation 

to  human  activities,  9 ;    relation 

to  plant  life,   9 ;    sources  of,   8 ; 

use  during  pregnancy,  264;    use 

in  work,  219. 
Oysters,  as  source  of  disease,  336. 

Pancreatic  juice,  the,  103. 

Paraglobulin,  50. 

Pectin,  74. 

Pentosans,  74. 

Pentoses,  68. 

Pepsin,  97. 

Peptones,  58. 

Phaseolin,  50. 

Phosphorus,  in  foods  and  flesh,  13  ; 

relation    to    brain    power,    150; 

sources,  13. 

Physiological  requirements,  176. 
Plant,  elements  in,   15 ;   relation  of 
2o 


animal  life  to,  4;  the,  stores 
substance,  3;  life,  relation  to 
oxygen,  9. 

Plasma,  the,  129. 

Poly-saccharides,  71. 

Potassium,  in  flesh,  14 ;  sources,  14. 

Pregnancy,  diet  during,  265;  en- 
ergy use  during,  263;  food  de- 
mands during,  263. 

Preservatives,  effect  on  health,  338 ; 
use  of,  339,  341-342. 

Production,  175. 

Protamines,  53. 

Protein,  circulatory,  195 ;  demands 
on,  196 ;  fixed,  195 ;  functions  of, 
151 ;  harmfulness  from  flesh,  249 ; 
kind  necessary,  248 ;  necessary 
supply,  19JL;  relation  to  health, 
197 ;  sparers  of,  172 ;  standards, 
196. 

Proteins,  alcohol  soluble,  52 ;  classi- 
fication of,  43 ;  coagulation  of, 
313 ;  composition  of,  46 ;  con- 
stitution of,  59 ;  digestibility  of, 
115;  familiar  examples,  47 ;  how 
used,  154 ;  oxidation  of,  136 ; 
properties  of,  58 ;  relative  effi- 
ciency of,  152 ;  simple,  47 ; 
true,  46 ;  unlike/  43. 

Proteoses,  58. 

Psychic  condition,  effect  on  child, 
277. 

Ptyalin,  94. 

Rennin,  97. 

Respiration  calorimeter,  145. 
Respiration,  relation  to  work,  220. 
Respiratory  quotient,  145. 
Rigor  mortis,  50. 

Saccharose,  69. 

Saliva,  the,  93;     action      of,     94; 

functions  of,  93  ;   origin  of,  94. 
Secretins,  100. 

Secretions,  influence  of  food  on,  119. 
Seeds,  fat  in,  79. 


450 


Index 


Sex,  relation  to  diet,  217. 

Skatol,  106. 

Social    welfare,    relation    to    food, 

243. 
Sodium,   relation  to  digestion,   14 ; 

source,  14. 

Soil  moisture,  effect  of,  30. 
Spongin,  53. 

Starch,  in  different  foods,  71. 
Starches,  the,  71 ;    digestibility  of, 

116. 

Steapsin,  97,  104. 
Stimuli,  chemical,  100  ;   gastric,  99  ; 

psychic,  100. 
Stomach,  the,  95. 
Sugar,  cane,  69. 
Sugars,    65 ;     classification   of,    66 ; 

digestibility  of,  116;   simple,  67. 
Sulfur,   relation  animal  tissue,   13 ; 

sources,  12. 

Temperament,  relation  to  diet,  218. 
Temperature,  the  critical,  169. 
Tissue,  built  from  food,  136. 
Toxins,  danger  from,  254. 
Trichinosis,  335. 
Trypsin,  104. 
Tuberculosis,  335. 
Tuberin,  50. 

Urea,  elimination  of,  137. 
Uric  acid,  formers  of,  252. 


Vegetables,  losses  in  cooking,  318; 
source  of  infection,  337 ;  un- 
healthy, 334. 

Vegetarianism,  246 ;  anatomical 
arguments,  247. 

Vegetarians,  physical  quality  of, 
255. 

Vicilin,  50. 

Vignin,  50. 

Vitellin,  51. 

Wastes,  elimination  of,  137. 

Water,  26;  determination  of,  26; 
elimination  of,  138  ;  functions  of, 
148  ;  hygroscopic,  27  ;  impurities 
in,  330 ;  in  animal,  31 ;  in  dry 
foods,  31;  in  living  plants,  28; 
in  immature  plants,  29 ;  physi- 
ological, 27  ;  proportion  in  plants, 
29 ;  pure,  330 ;  sanitary,  331  ; 
source  of  disease,  329. 

Weight,  relation  to  diet,  216. 

Woman,  period  of  lactation,  269. 

Work,  external,  218;  internal,  218; 
oxygen  requirement,  219 ;  rela- 
tion to  diet,  218;  relation  to 
alcohol,  310 ;  relation  to  blood 
flow,  220  ;  relation  to  respiration, 
220. 

Zein,  52. 
Zylose,  74. 


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